X0306 4 2021-09-27 0 0001866757 Brilliant Earth Group, Inc. BRLT 0001883360 MAINSAIL GP III, LLC C/O MAINSAIL MANAGEMENT COMPANY, LLC 500 WEST 5TH STREET, SUITE 1100 AUSTIN TX 78701 0 0 1 0 0001543760 Mainsail Partners III, L.P. C/O MAINSAIL MANAGEMENT COMPANY, LLC 500 WEST 5TH STREET, SUITE 1100 AUSTIN TX 78701 0 0 1 0 0001570211 Mainsail Co-Investors III, L.P. C/O MAINSAIL MANAGEMENT COMPANY, LLC 500 WEST 5TH STREET, SUITE 1100 AUSTIN TX 78701 0 0 1 0 0001883293 MAINSAIL INCENTIVE PROGRAM, LLC C/O MAINSAIL MANAGEMENT COMPANY, LLC 500 WEST 5TH STREET, SUITE 1100 AUSTIN TX 78701 0 0 1 0 0001883367 MAINSAIL MANAGEMENT COMPANY, LLC C/O MAINSAIL MANAGEMENT COMPANY, LLC 500 WEST 5TH STREET, SUITE 1100 AUSTIN TX 78701 0 0 1 0 Class B Common Stock 2021-09-27 4 D 0 469824 D 31965771 I See footnote LLC Units 2021-09-27 4 D 0 469824 11.22 D Class A Common Stock 469824 31965771 I See footnote On September 27, 2021, the Issuer used a portion of the net proceeds from the closing of its initial public offering ("IPO") of Class A common stock to redeem common units of Brilliant Earth LLC (the "LLC Units") from the reporting persons, at a price of $11.22 per LLC Unit (the "Redemption"). One share of the Issuer's Class B common stock for every LLC Unit redeemed was forfeited and canceled for no consideration in connection with the Redemption. Consists of (i) 458,769 shares of Class B common stock forfeited by Mainsail Partners III, L.P. ("MP III"), (ii) 912 shares of Class B common stock forfeited by Mainsail Incentive Program, LLC ("MIP"), and (iii) 10,143 shares of Class B common stock forfeited by Mainsail Co-Investors III, L.P. ("MCOI"), in each case, in connection with the Redemption. Consists of (i) 31,213,636 shares of Class B common stock (and associated LLC Units) held by Mainsail Partners III, L.P. ("MP III"), (ii) 62,051 shares of Class B common stock (and associated LLC Units) held by Mainsail Incentive Program, LLC ("MIP"), and (iii) 690,084 shares of Class B common stock (and associated LLC Units) held by Mainsail Co-Investors III, L.P. ("MCOI"). 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 sole Manager of MMC. Mr. Turner has separately reported the securities held by each of the foregoing on his Form 3 filed in his capacity as a director of the Issuer. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their respective pecuniary interests therein. 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. LLC Units do not expire. /s/ Gavin Turner, Mainsail GP III, LLC 2021-09-28 /s/ Gavin Turner, Mainsail Partners III, L.P. 2021-09-28 /s/ Gavin Turner, Mainsail Co-Investors III, L.P. 2021-09-28 /s/ Gavin Turner, Mainsail Incentive Program, LLC 2021-09-28 /s/ Gavin Turner, Mainsail Management Company, LLC 2021-09-28