Brilliant Earth Group, Inc.

(a) None.

(b) None.

(c) Except as described below, during the three months ended September 30, 2025, no directors or “officers” (as defined in Rule 16a-1(f) under the Exchange Act) of the Company adopted, modified orterminated “Rule 10b5-1 trading arrangements” and/or “non-Rule 10b5-1 trading arrangements” (each as defined in Item 408 of Regulation S-K).

On August 11, 2025, Mainsail Partners III, L.P., Mainsail Co-Investors III, L.P. and Mainsail Incentive Program, LLC (together, the “Mainsail Entities”), terminated an existing Rule 10b5-1 trading arrangement (the "Mainsail Sales Plan") which was adopted by the Mainsail Entities on December 11, 2024 that was intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and which provided for the sale of an aggregate of up to 1,000,000 shares of the Company's Class A common stock until August 28, 2025. Gavin Turner, a member of the Company’s Board of Directors, is the Managing Partner of Mainsail Management Company, LLC and may be deemed to have a pecuniary interest in the Class A common stock owned by the Mainsail Entities.

On August 13, 2025, Sharon Dziesietnik, the Company's Chief Operations Officer, terminated an existing Rule 10b5-1 trading arrangement (the "Dziesietnik Sales Plan") which was adopted by Ms. Dziesietnik on June 2, 2024 that was intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and which provided for the sale of an aggregate of up to 44,524 shares of the Company's Class A common stock (a portion of the shares of Class A common stock to be received by Ms. Dziesietnik upon the vesting of restricted stock units as set forth in the Dziesietnik Sales Plan) until August 30, 2025.

On August 14, 2025, Ms. Dziesietnik, adopted a Rule 10b5-1 trading arrangement (the "2025 Dziesietnik Sales Plan") that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and which provides for the sale of an aggregate of up to 49,128 shares of the Company's Class A common stock (a portion of the shares of Class A common stock to be received by Ms. Dziesietnik upon the vesting of restricted stock units as set forth in the 2025 Dziesietnik Sales Plan). The 2025 Dziesietnik Sales Plan will remain in effect until the earliest of (1)August 30, 2026, (2) the date on which all trades set forth in the 2025 Dziesietnik Sales Plan have been executed, or (3) such time as the 2025 Dziesietnik Sales Plan is otherwise terminated or expires according to its terms.

On August 27, 2025, Jennifer Harris, a member of the Company's Board of Directors, adopted a Rule 10b5-1 trading arrangement (the "Harris Sales Plan") that is intended to satisfy the affirmative defense of

Rule 10b5-1(c) of the Exchange Act and which provides for the sale of an aggregate of up to 40,856 shares of the Company's Class A common stock. The Harris Sales Plan will remain in effect until the earliest of (1)June 30, 2026, (2) the date on which all trades set forth in the Harris Sales Plan have been executed, or (3) such time as the Harris Sales Plan is otherwise terminated or expires according to its terms.

On August 15, 2025, Just Rocks, Inc., a Delaware corporation which is jointly owned and controlled by Beth Gerstein, the Company’s Chief Executive Officer and a member of the Board of Directors, and Eric Grossberg, the Company’s Executive Chairman, adopted a Rule 10b5-1 trading arrangement (the “Just Rocks Sales Plan”) that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and which provides for the sale of an aggregate of up to 1,500,000 shares of Class A common stock. The Just Rocks Sales Plan will remain in effect until the earliest of (1)July 17, 2026, (2) the date that the aggregate number of shares sold pursuant to the Just Rocks Sales Plan reaches 1,500,000 shares, or (3) such time as the Just Rocks Sales Plan is otherwise terminated or expires according to its terms.

On September 8, 2025, Mr. Jeffrey Kuo, the Company's Chief Financial Officer, adopted a Rule 10b5-1 trading arrangement (the "Kuo Sales Plan") that is intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and which provides for the sale of an aggregate of up to 44,044 shares of the Company's Class A common stock (a portion of the shares of Class A common stock to be received by Mr. Kuo upon the vesting of restricted stock units as set forth in the Kuo Sales Plan). The Kuo Sales Plan will remain in effect until the earliest of (1)May 22, 2026, (2) the date on which all trades set forth in the Kuo Sales Plan have been executed, or (3) such time as the Kuo Sales Plan is otherwise terminated or expires according to its terms.