SOUTHSTONE REPORTS Q3 2026 DIAMOND SALES RESULTS AND APPOINTMENT OF INDEPENDENT DIRECTOR AND CHIEF FINANCIAL OFFICER

Southstone Minerals Limited delivered solid Q3 2026 diamond sales results from its Oena Diamond Mine operation in South Africa, generating gross proceeds of US$4.73 million from 2,132 carats sold across three tenders. The average realized price of US$2,220 per carat represents strong performance, bolstered by 32 special diamonds over 10.8 carats that contributed approximately 63% of gross sales value. A standout 8.233 carat fancy yellow diamond achieved US$21,715 per carat, marking the highest per-carat price realized at Oena since production commenced in 2015.

The operational outlook presents near-term challenges as mining at the current Sandberg S7 Basal section approaches pit limits. The contract miner has advised that six to eight weeks of overburden stripping will be required to open a new pit along strike, during which diamond recoveries are expected to decline. However, recent production sorts have already recovered an additional 434.55 carats, including nine special diamonds totaling 229.05 carats awaiting sale in Q4 2026.

From a corporate governance perspective, Southstone has addressed critical TSX Venture Exchange compliance deficiencies through key appointments effective May 25, 2026. Kevin Ma joined as an independent director and Audit Committee Chair, while Derek Sobel was appointed as Chief Financial Officer, creating the required separation of CEO and CFO roles. These appointments resolve the exchange's concerns regarding board independence and committee composition.

Since acquiring Oena in 2015, Southstone has achieved cumulative gross diamond sales of US$28.37 million from 15,464 carats, establishing an average price of US$1,835 per carat over the mine's operating history. The company also completed repayment of its CC Mining loan, eliminating this debt obligation and strengthening its balance sheet position as it navigates the upcoming operational transition period.