Mr. Terry Tucker reports

SOUTHSTONE'S SUBSIDIARY, AFRICAN STAR MINERALS, PARTICIPATES IN USD $1.9M DIAMOND SALES TO JUNE 2025; SANDBERG SECTION DRIVES PERFORMANCE

Southstone Minerals Ltd. has released diamond production and sales results from its majority-owned Oena diamond mine in the Republic of South Africa for the period covering Q2 (second quarter) and Q3 (third quarter) 2025 (December, 2024, to May, 2025), and the month of June, 2025. The Sandberg section continues to deliver strong operational results, including higher average stone sizes and multiple high-value special diamonds. A sale for an additional 12.3 carats recovered in June, 2025, remains pending. African Star Minerals Pty. Ltd. (ASM), Southstone's 43-per-cent-owned subsidiary and the holder of the Oena mining licence, has a contract mining and diamond recovery agreement with Rietput Delwery Pty. Ltd., under which ASM is entitled to receive 20 per cent of the gross diamond sales revenue, net of tender house commissions and sale-related expenses. Southstone's effective interest in this revenue is 8.6 per cent, providing direct exposure to diamond sales performance while maintaining a lean operational model.

Key highlights (December, 2024, to June, 2025)

Q2 to June, 2025, performance transformation:

• Production source: shifted from the Oena Proper section to the Sandberg section (97 to 100 per cent);
• Average diamond size: increased from 2.08 carats (ct) to 4.72 ct (plus 127 per cent);
• Price realization: increased from $826 to $2,421 per carat (plus 193 per cent), reflecting improved recovery of high-value diamonds from the Sandberg section;
• Special stones: 13 diamonds more than 10.8 ct averaging 31.3 ct each.

Q2 2025 (December, 2024, to February, 2025):

• 118.45 ct sold (57 diamonds) from the Oena Proper section;
• Average price: $826 (U.S.) per carat;
• Total revenue: $97,900 (U.S.).

Q3 2025 (March, 2025, to May, 2025):

• 614.47 ct sold (132 diamonds), 97 per cent from the Sandberg section;
• Average price: $1,496 (U.S.) per carat;
• Total revenue: $919,647 (U.S.).

June, 2025 (start of Q4 (fourth quarter)):

• 369.82 ct sold (100 per cent from the Sandberg section);
• Average price: $2,421 (U.S.) per carat;
• Total revenue: $895,203 (U.S.);
• An additional 12.3 ct remain pending sale.

"These results demonstrate the potential we've long believed exists in the Sandberg section," said Terry L. Tucker, PGeo, executive chairman. "With our operational team and contractor working in unison, we're well positioned to continue extracting value from this proven high-grade zone while exploring additional opportunities within our licence area."

Special-size diamond sales -- Sandberg section (April to June, 2025):

• Thirteen special-size diamonds (more than 10.8 carats) were recovered from the Sandberg section, averaging 31.3 ct each.
• These specials sold for a total of $1,225,552 (U.S.) (included in the overall revenue).

Additional special stones:

• Three larger stones (82.11 ct, 45.94 ct and 13.48 ct) were sold collectively for $32,381 (U.S.). While of lower individual value, these large stones reflect the continuing potential for discovery of high-carat diamonds from Sandberg.

Mid-size stones (4.17 to 9.89 ct):

• Sixteen diamonds were sold for a combined $332,399 (U.S.), with an average sale price of $20,775 (U.S.) per stone.

In February, 2025, production shifted from the Oena Proper section to the Sandberg section following the appointment of a new contractor, Rietput. Mobilization occurred in February and March, with deployment of heavy equipment, including two 16-foot pans and a Bourevestnik X-ray unit. Between April and June, 2025, Rietput focused on mining basal scours and push bars within the Sandberg section, resulting in a significant increase in diamond production from this established source of high-value stones.

The successful deployment of Rietput as contractor has materially improved recovery rates and is expected to support continued operational excellence as the company advances its strategy to focus on high-value production zones.

With Rietput's heavy equipment now fully deployed and operational procedures optimized, management anticipates the Sandberg section will continue to be the primary focus of mining activities. The section's demonstrated capacity to produce special-size diamonds at premium prices provides a strong foundation for the company's operational strategy going forward.

Since the acquisition of Oena in 2014, the company has recorded total diamond production of 10,614 carats with an average stone size of 2.04 carats and an average sales price of $1,643 (U.S.) per carat.

Southstone manages Oena, and is responsible for diamond sales, operational and mining consultation with the contractor, compliance with mining licence reporting requirements, and site security. The company maintains a management and security team in South Africa, including the chief executive officer of African Star Minerals and the Oena operational site manager. The company's executive chairman, supported by an external geological consultant, provides internal reporting oversight and delivers geological and technical support to the operations team and contractors.

Southstone receives a fixed management fee of $20,000 (U.S.) per month from African Star Minerals, which finances its Canadian corporate operations. This amount is not directly tied to monthly sales but is supported by African Star's 20-per-cent share of gross diamond sales under its contract mining agreement. Combined with its equity participation, this structure provides Southstone with both stable operational income and direct exposure to diamond sales performance.

The technical disclosure in this news release has been reviewed and approved by Terry L. Tucker, PGeo, executive chairman of Southstone Minerals and a qualified person as defined by National Instrument 43-101 of the Canadian Securities Administrators.

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