Mr. Terry Tucker reports

SOUTHSTONE REPORTS PARTIAL Q3 2026 DIAMOND SALES RESULTS

Southstone Minerals Ltd. had diamond sales results from the Oena diamond mine in South Africa for tenders 275 and 276, the first two tenders of fiscal Q3 2026 (March to May, 2026). Gross diamond sales totalled $2,078,798 (U.S.) from 1,043 carats sold at an average of $1,993 (U.S.) per carat. Fifteen special diamonds (greater than 10.8 carats) accounted for approximately 63 per cent of gross sales value. Mining continues at the Sandberg S7 Basal section of the Oena diamond mine.

Q3 2026 highlights -- tenders 275 and 276 (March 19 and April 23, 2026):

• Gross diamond sales: $2,078,798 (U.S.); the March 19, 2026, sale ($1,196,470 (U.S.)) was the second-highest single-month result since the company acquired Oena in 2014;
• Carats sold: 1,043 carats across 375 diamonds;
• Average price: $1,993 (U.S.) per carat, approximately 2 per cent below the average price of $2,027 (U.S.) per carat realized since January, 2024;
• Specials: 15 special diamonds (greater than 10.8 carats) sold, averaging 17 carats each, for combined proceeds of $1,301,625 (U.S.), representing 63 per cent of gross sales value;
• Revenue split: the 80/20 split between Rietput Delwery BK and African Star Minerals Pty. Ltd. applied, as gross South African rand sales exceeded the 10-million-South-African-rand threshold; Southstone's effective economic interest is 8.60 per cent;
• Unsold inventory: 590 carats, including eight special diamonds averaging 15.30 carats each, remain in inventory from the April 26 and 27 production sorts, pending the May 21, 2026, tender;
• Mining continues: operations are continuing at the Sandberg S7 Basal section of the Oena diamond mine.

Tender 275 and 276 -- revenue split

African Star is party to a contract mining and diamond recovery agreement with Rietput. Effective July 1, 2025, gross diamond sales (net of tender costs) are split 80/20 between Rietput and African Star when individual tender gross South African rand sales equal or exceed 10 million South African rand and 85/15 when below that threshold. Tenders 275 and 276 exceeded the threshold.

Unsold inventory

Subsequent to Tender 276, the company holds 590 carats in unsold inventory from the April 26 and 27 production sorts. This parcel includes eight special diamonds averaging 15.30 carats each. These diamonds are pending sale at the May 21, 2026, tender.

Operations overview

Southstone, through African Star, provides operational oversight at Oena, including diamond sales administration, contractor liaison, mining licence compliance and security. The company maintains a management and security team in South Africa, including the chief executive officer of African Star and the Oena operational site manager. The company's executive chairman, with external geological support, provides operational support for internal reporting of Oena activities and geological and technical support to the operations team and contractors.

Qualified person statement

The technical disclosure in this news release relating to diamond production, recovery and sales has been approved by Terry L. Tucker, PGeo (APEGBC), executive chairman and a qualified person as defined by National Instrument 43-101 of the Canadian Securities Administrators. Mr. Tucker has verified the production and sales records disclosed in this release.

We seek Safe Harbor.