BRLT

SEC source: 0001193125-26-368530 · ownership.xml · derivative · entry 2

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Underlying: Class A Common Stock · 16,014 shares

Expires not disclosed

F4 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Persons prior to the Issuer's initial public offering, do not expire.

F1 · kind: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · price: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F4 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Persons prior to the Issuer's initial public offering, do not expire.

F4 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Persons prior to the Issuer's initial public offering, do not expire.

F1 · derivative.underlying_shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F2 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F2 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-368530 · ownership.xml · nonDerivative · entry 1

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

F1 · kind: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · price: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Persons' pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Persons on August 12, 2026. Accordingly, the Reporting Persons have fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F2 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F2 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-368536 · ownership.xml · derivative · entry 2

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Underlying: Class A Common Stock · 16,014 shares

Expires not disclosed

F4 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Person prior to the Issuer's initial public offering, do not expire.

F1 · kind: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · price: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F4 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Person prior to the Issuer's initial public offering, do not expire.

F4 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the Reporting Person prior to the Issuer's initial public offering, do not expire.

F1 · derivative.underlying_shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F2 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F2 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the Reporting Person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the Reporting Person is the sole Manager of MMC. The Reporting Person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001193125-26-368536 · ownership.xml · nonDerivative · entry 1

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

F1 · kind: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · shares: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F1 · price: The reported transaction, which involves a purchase of a limited partner's interest in Mainsail Co-Investors III, L.P. ("MCOI"), may represent a change in the Reporting Person's pecuniary interest in common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock held by MCOI. For purposes of Section 16(b), such deemed purchase, for an aggregate consideration of $18,096, could be matchable against the sales reported on August 10, 2026, as reported on the Form 4 filed by the Reporting Person on August 12, 2026. Accordingly, the Reporting Person has fully disgorged to the Issuer, the Section 16(b) deemed profit of $2,033.

F2 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F2 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the Reporting Person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the Reporting Person is the sole Manager of MMC. The Reporting Person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001628280-26-058095 · wk-form4_1787183107.xml · nonDerivative · entry 2

Gerstein Beth Tamara · CIK 0001883883 · Director · Chief Executive Officer · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,000

F2 · price: This transaction was executed in multiple trades ranging from $1.25 to $1.26. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

F3 · balance_after: The shares purchased in the transactions reported herein are in addition to the LLC Interests (and associated shares of Class C common stock that are convertible into shares of Class A common stock) held by Just Rocks, Inc. Just Rocks, Inc. is jointly owned and controlled by the reporting person and Eric Scott Grossberg.

SEC source: 0001628280-26-058094 · wk-form4_1787183099.xml · nonDerivative · entry 2

Grossberg Eric Scott · CIK 0001884137 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote below

Disclosed balance after: 10,000

F3 · balance_after: The shares purchased in the transactions reported herein are in addition to the LLC Interests (and associated shares of Class C common stock that are convertible into shares of Class A common stock) held by Just Rocks, Inc. Just Rocks, Inc. is jointly owned and controlled by the reporting person and Beth Tamara Gerstein.

F2 · ownership.nature: Represents shares purchased by The Eric S. Grossberg Revocable Trust, for which Mr. Grossberg serves as the Trustee and has voting power and investment power over such shares.

SEC source: 0001628280-26-058095 · wk-form4_1787183107.xml · nonDerivative · entry 1

Gerstein Beth Tamara · CIK 0001883883 · Director · Chief Executive Officer · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,797

F1 · price: This transaction was executed in multiple trades ranging from $1.16 to $1.29. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-26-058094 · wk-form4_1787183099.xml · nonDerivative · entry 1

Grossberg Eric Scott · CIK 0001884137 · Director · Executive Chairman · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote below

Disclosed balance after: 9,619

F1 · price: This transaction was executed in multiple trades ranging from $1.16 to $1.30. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

F2 · ownership.nature: Represents shares purchased by The Eric S. Grossberg Revocable Trust, for which Mr. Grossberg serves as the Trustee and has voting power and investment power over such shares.

SEC source: 0001628280-26-057934 · wk-form4_1787169744.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 532,448

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 14, 2025.

F2 · price: This transaction was executed in multiple trades ranging from $1.19 to $1.36. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-26-057223 · wk-form4_1786967880.xml · nonDerivative · entry 1

Kuo Jeffrey Chuenhong · CIK 0001881502 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 693,130

F1 · price: This transaction was executed in multiple trades ranging from $1.31 to $1.41. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001193125-26-347377 · ownership.xml · derivative · entry 4

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Underlying: Class A Common Stock · 50,000 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F2 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F2 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F3 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-347377 · ownership.xml · nonDerivative · entry 3

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 0

F4 · kind: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F5 · price: This transaction was executed in multiple trades at prices ranging from $1.25 to $1.40, inclusive. The reported price reflects the weighted average sale price. The reporting persons hereby undertake to provide upon request to the United States Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transaction was affected.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-347377 · ownership.xml · nonDerivative · entry 2

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 50,000

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-347377 · ownership.xml · nonDerivative · entry 1

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F3 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0001193125-26-347375 · ownership.xml · derivative · entry 4

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Underlying: Class A Common Stock · 50,000 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F2 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F2 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F3 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001193125-26-347375 · ownership.xml · nonDerivative · entry 3

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 0

F4 · kind: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F5 · price: This transaction was executed in multiple trades at prices ranging from $1.25 to $1.40, inclusive. The reported price reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the United States Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transaction was affected.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001193125-26-347375 · ownership.xml · nonDerivative · entry 2

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 50,000

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001193125-26-347375 · ownership.xml · nonDerivative · entry 1

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 31,848,071

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 48,824 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 97 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 1,079 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F3 · balance_after: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,098,704 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,823 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 687,544 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.

SEC source: 0001628280-26-044956 · wk-form4_1782248046.xml · nonDerivative · entry 2

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 213,966

F1 · shares: The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 27, 2025.

F3 · price: This transaction was executed in multiple trades ranging from $1.01 to $1.06. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-26-044956 · wk-form4_1782248046.xml · nonDerivative · entry 1

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 232,302

F1 · shares: The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 27, 2025.

F2 · price: This transaction was executed in multiple trades ranging from $1.04 to $1.12. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-26-044451 · wk-form4_1781827462.xml · nonDerivative · entry 1

KAPLAN BETH J · CIK 0001247154 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 293,934

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $95,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2027 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001628280-26-044452 · wk-form4_1781827468.xml · nonDerivative · entry 1

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 252,322

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $95,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2027 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001628280-26-044450 · wk-form4_1781827456.xml · nonDerivative · entry 1

Jaques Attica · CIK 0001848115 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 288,234

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $95,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2027 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001628280-26-036888 · wk-form4_1779307767.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 542,572

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 14, 2025.

F2 · price: This transaction was executed in multiple trades ranging from $1.12 to $1.21. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-26-016442 · wk-form4_1773173758.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 552,696

F1 · shares: Grant of restricted stock unit award under the Issuer's 2021 Incentive Award Plan. The award will vest as to 25% of the restricted stock units initially subject to the award on February 15, 2026 and as to 1/16th of the restricted stock units initially subject to the award on each quarterly anniversary thereafter until the award is fully vested, subject to the reporting person's continuing to provide services to the Issuer or its subsidiaries through the applicable vesting date.

SEC source: 0001628280-26-016446 · wk-form4_1773173809.xml · nonDerivative · entry 1

Kuo Jeffrey Chuenhong · CIK 0001881502 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 683,130

F1 · shares: Grant of restricted stock unit award under the Issuer's 2021 Incentive Award Plan. The award will vest as to 25% of the restricted stock units initially subject to the award on February 15, 2026 and as to 1/16th of the restricted stock units initially subject to the award on each quarterly anniversary thereafter until the award is fully vested, subject to the reporting person's continuing to provide services to the Issuer or its subsidiaries through the applicable vesting date.

SEC source: 0001628280-26-010301 · wk-form4_1771625547.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 446,736

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 14, 2025.

F2 · price: This transaction was executed in multiple trades ranging from $1.28 to $1.47. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001628280-25-053167 · wk-form4_1763586388.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 466,423

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 14, 2025.

F2 · price: This transaction was executed in multiple trades ranging from $1.925 to $2.11. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001866757-25-000093 · wk-form4_1750287774.xml · nonDerivative · entry 3

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 83,913

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 3, 2024.

F4 · price: This transaction was executed in multiple trades ranging from $1.33 to $1.37. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001866757-25-000106 · wk-form4_1750716366.xml · nonDerivative · entry 1

Bickley Ian · CIK 0001632468 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 244,163

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $140,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2026 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001866757-25-000105 · wk-form4_1750716354.xml · nonDerivative · entry 1

KAPLAN BETH J · CIK 0001247154 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 221,415

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $140,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2026 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001866757-25-000104 · wk-form4_1750716344.xml · nonDerivative · entry 1

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 179,803

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $140,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2026 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001866757-25-000103 · wk-form4_1750716243.xml · nonDerivative · entry 1

Jaques Attica · CIK 0001848115 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 215,715

F1 · shares: Grant of a restricted stock unit award under the Issuer's compensation program for non-employee directors which provides for an annual grant of restricted stock units to non-employee directors calculated by dividing (a) $140,000 by (b) the average closing trading price of the Issuer's Class A common stock over the most recent completed month as of the grant date, rounded down to the nearest whole restricted stock unit. The award will vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2026 annual stockholder's meeting, subject to continued service through the applicable vesting date.

SEC source: 0001866757-25-000093 · wk-form4_1750287774.xml · nonDerivative · entry 2

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 89,230

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 3, 2024.

F3 · price: This transaction was executed in multiple trades ranging from $1.32 to $1.38. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001866757-25-000093 · wk-form4_1750287774.xml · nonDerivative · entry 1

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 96,333

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. The transactions reported herein were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 3, 2024.

F2 · price: This transaction was executed in multiple trades ranging from $1.36 to $1.40. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001866757-25-000087 · wk-form4_1748899356.xml · nonDerivative · entry 1

Bickley Ian · CIK 0001632468 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,419

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000086 · wk-form4_1748899346.xml · nonDerivative · entry 1

Jaques Attica · CIK 0001848115 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,419

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000080 · wk-form4_1747696325.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 475,614

F1 · shares: Shares of Class A common stock sold by the reporting person to cover estimated tax obligations in connection with the vesting and settlement of restricted stock units. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 12, 2024

F2 · price: This transaction was executed in multiple trades ranging from $1.34 to $1.53. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

SEC source: 0001866757-25-000069 · wk-form4_1746132748.xml · nonDerivative · entry 1

Bickley Ian · CIK 0001632468 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,814

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000070 · wk-form4_1746132759.xml · nonDerivative · entry 1

Jaques Attica · CIK 0001848115 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,814

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000048 · wk-form4_1743538079.xml · nonDerivative · entry 1

Bickley Ian · CIK 0001632468 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,243

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000049 · wk-form4_1743538090.xml · nonDerivative · entry 1

Harris Jennifer Noel · CIK 0001597649 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 41,215

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000047 · wk-form4_1743538067.xml · nonDerivative · entry 1

Jaques Attica · CIK 0001848115 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,243

F1 · price: Reflects the acquisition for no consideration of Class B Common Stock in connection with the vesting of Common Units.

SEC source: 0001866757-25-000043 · wk-form4_1743192333.xml · nonDerivative · entry 1

Dziesietnik Sharon · CIK 0002035090 · Chief Operations Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 484,804

F1 · shares: Grant of restricted stock unit award under the Issuer's 2021 Incentive Award Plan. The award will vest as to 25% of the restricted stock units initially subject to the award on February 15, 2026 and as to 1/16th of the restricted stock units initially subject to the award on each quarterly anniversary thereafter until the award is fully vested, subject to the reporting person's continuing to provide services to the Issuer or its subsidiaries through the applicable vesting date.

SEC source: 0001866757-25-000042 · wk-form4_1743192321.xml · nonDerivative · entry 1

Kuo Jeffrey Chuenhong · CIK 0001881502 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 570,548

F1 · shares: Grant of restricted stock unit award under the Issuer's 2021 Incentive Award Plan. The award will vest as to 25% of the restricted stock units initially subject to the award on February 15, 2026 and as to 1/16th of the restricted stock units initially subject to the award on each quarterly anniversary thereafter until the award is fully vested, subject to the reporting person's continuing to provide services to the Issuer or its subsidiaries through the applicable vesting date.

SEC source: 0000950170-25-040443 · ownership.xml · derivative · entry 4

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 31,898,071

Underlying: Class A Common Stock · 2,700 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F2 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F2 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F3 · balance_after: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0000950170-25-040443 · ownership.xml · nonDerivative · entry 3

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Indirect · See footnote

Disclosed balance after: 0

F4 · kind: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F5 · price: This sale of shares of Class A common stock was executed pursuant to a Rule 10b5-1 plan that was entered into by the reporting persons during an open trading window. This transaction was executed in multiple trades at prices ranging from $1.75 to $1.94, inclusive. The reported price reflects the weighted average sale price. The reporting persons hereby undertake to provide upon request to the United States Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transaction was affected.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0000950170-25-040443 · ownership.xml · nonDerivative · entry 2

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Indirect · See footnote

Disclosed balance after: 2,700

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0000950170-25-040443 · ownership.xml · nonDerivative · entry 1

MAINSAIL GP III, LLC · CIK 0001883360 · 10% owner

Mainsail Partners III, L.P. · CIK 0001543760 · 10% owner

Mainsail Co-Investors III, L.P. · CIK 0001570211 · 10% owner

MAINSAIL INCENTIVE PROGRAM, LLC · CIK 0001883293 · 10% owner

MAINSAIL MANAGEMENT COMPANY, LLC · CIK 0001883367 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 31,898,071

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting persons prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F1 · price: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F3 · balance_after: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with Gavin Turner possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and Gavin Turner is the sole Manager of MMC. Mr. Turner has separately reported the transactions and reported securities reflected in this statement. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein.

SEC source: 0000950170-25-040411 · ownership.xml · derivative · entry 4

TURNER GAVIN · CIK 0001883427 · Director · 10% owner

10b5-1 filing: Plan reported

Ownership: Indirect · See footnotes

Disclosed balance after: 31,898,071

Underlying: Class A Common Stock · 2,700 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F1 · kind: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · kind: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F1 · shares: Represents common units of Brilliant Earth, LLC (the "LLC Units") and shares of Class B common stock exchanged for shares of Class A common stock including (i) 2,637 LLC Units and shares of Class B common stock exchanged by Mainsail Partners III, L.P. ("MP III"), (ii) 5 LLC Units and shares of Class B common stock exchanged by Mainsail Incentive Program, LLC ("MIP"), and (iii) 58 LLC Units and shares of Class B common stock exchanged by Mainsail Co-Investors III, L.P. ("MCOI").

F2 · price: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F2 · derivative.exercise_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F2 · derivative.expiration_date: LLC Units (together with one share of Class B common stock for every LLC Unit) are exchangeable for one share of the Issuer's Class A common stock. The reported LLC Units, which were acquired by the reporting person prior to the Issuer's initial public offering, do not expire.

F3 · balance_after: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F3 · ownership.nature: Consists of (i) 31,147,528 shares of Class B common stock (and associated LLC Units) held by MP III, (ii) 61,920 shares of Class B common stock (and associated LLC Units) held by MIP, and (iii) 688,623 shares of Class B common stock (and associated LLC Units) held by MCOI.

F4 · ownership.nature: Mainsail GP III, LLC ("GP III") is the general partner of MP III. MCOI is a co-investment vehicle that invests alongside MP III. GP III is the general partner of MCOI. A three member investment committee of GP III acts by a majority vote, with the reporting person possessing a veto right, with respect to the voting and dispositive power of the securities held by MP III and MCOI. Mainsail Management Company, LLC ("MMC") is the managing member of MIP, and the reporting person is the sole Manager of MMC. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interests therein.