VICTORIA, BRITISH COLUMBIA — 3 JULY 2025 — Southstone Minerals Limited (“Southstone” or the “Company”) (TSX.V – SML) reports diamond production and sales results from its majority-owned Oena Diamond Mine (“Oena”) in the Republic of South Africa for the period covering Q2 and Q3 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%-owned subsidiary and the holder of the Oena mining license, has a contract mining and diamond recovery agreement with Rietput Delwery (Pty) Ltd under which ASM is entitled to receive 20% 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%, providing direct exposure to diamond sales performance while maintaining a lean operational model.
Key Highlights (December 2024 – June 2025):
Q2 to June 2025 Performance Transformation:
- Production Source: Shifted from Oena Proper to Sandberg Section (97-100%)
- Average Diamond Size: Increased from 2.08ct to 4.72ct (+127%)
- Price Realization: Increased from $826 to $2,421 per carat (+193%) reflecting improved recovery of high-value diamonds from the Sandberg Section.
- Special Stones: 13 diamonds >10.8ct averaging 31.3ct each
Q2 2025 (December 2024 – February 2025):
- 118.45 carats sold (57 diamonds) from the Oena Proper Section
- Average price: USD $826 per carat
- Total revenue: USD $97,900
Q3 2025 (March 2025 – May 2025):
- 614.47 carats sold (132 diamonds), 97% from Sandberg Section
- Average price: USD $1,496 per carat
- Total revenue: USD $919,647
June 2025 (start of Q4):
- 369.82 carats sold (100% from Sandberg Section)
- Average price: USD $2,421 per carat
- Total revenue: USD $895,203
- An additional 12.3 carats remain pending sale
“These results demonstrate the potential we’ve long believed exists in the Sandberg Section.” said Terry L. Tucker, P.Geo, 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 license area.”
Special Size Diamond Sales – Sandberg Section (April–June 2025)
- Thirteen Special Size Diamonds (>10.8 carats) were recovered from the Sandberg Section, averaging 31.3 carats each.
- These Specials sold for a total of USD $1,225,552 (included in the overall revenue).
Additional Special Stones
- Three larger stones (82.11 ct, 45.94 ct, and 13.48 ct) sold collectively for USD $32,381.
While of lower individual value, these large stones reflect the ongoing potential for discovery of high-carat diamonds from Sandberg.
Mid-Size Stones (4.17 – 9.89 ct)
- Sixteen diamonds sold for a combined USD $332,399, with an average sale price of USD $20,775 per stone.
Top 10 Special Stones
| Carat Weight | Sale Price (USD) | Price per Carat (USD) |
| 23.31 ct | $339,277 | $14,553 |
| 34.51 ct | $175,035 | $5,072 |
| 47.15 ct | $161,161 | $3,418 |
| 23.36 ct | $120,888 | $5,175 |
| 18.53 ct | $108,770 | $5,870 |
| 36.61 ct | $96,174 | $2,627 |
| 23.45 ct | $58,672 | $2,502 |
| 31.98 ct | $47,588 | $1,488 |
| 15.58 ct | $45,605 | $2,928 |
| 11.29 ct | $40,001 | $3,545 |
| Subtotal (Top 10 Specials): | USD $1,193,171 |
In February 2025, production shifted from the Oena Proper Section to the Sandberg Section following the appointment of a new contractor, Rietput Delwery (Pty) Ltd (“Rietput”). Mobilization occurred in February and March, with deployment of heavy equipment, including two 16-foot pans and a Bourevestnik X-Ray unit. Between April and June 2025, Rietput focused on mining basal scours and push bars within the Sandberg Section, resulting in a significant increase in diamond production from this established source of high-value stones (see Table 1).
The successful deployment of Rietput Delwery (Pty) Ltd as contractor has materially improved recovery rates and is expected to support continued operational excellence as the Company advances its strategy to focus on high-value production zones.
With Rietput’s heavy equipment now fully deployed and operational procedures optimized, management anticipates the Sandberg Section will continue to be the primary focus of mining activities. The section’s demonstrated capacity to produce special size diamonds at premium prices provides a strong foundation for the Company’s operational strategy going forward.
| Sandberg Section mining period | Total carats produced | Total Number of Diamonds | Average Diamond Size (carats) | USD ($)
per carat |
Total USD
Sales ($) |
| Sep 2018 to Nov 2021 | 2,690 | 1,157 | 2.33 | NA | NA |
| Nov 2023 to Aug 2024 | 769 | 319 | 2.41 | 1,935 | 1,488,051 |
| Apr 2025 to Jun 2025 | 981 | 208 | 4.72 | 1,8711 | 1,810,3511 |
Table 1 – Sandberg Section 2018 to 2025 diamond production and sales (1) pending sale of six stones
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 USD $1,643 per carat.
| Oena mining
period |
Total carats produced | Total Number of Diamonds | Average Diamond Size (carats) | USD ($)
per carat |
Total USD
Sales ($) |
| Jul 2015 to Jun 2025 | 10,614 | 5,192 | 2.04 | 1,6431 | 17,438,0501 |
Table 2 – Oena Mine 2015 to 2025 diamond production and sales; (1) pending sale of six June 2025 stones
Southstone manages Oena and is responsible for diamond sales, operational and mining consultation with the contractor, compliance with mining license reporting requirements and site security. The Company maintains a management and security team in South Africa, including the CEO 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 USD $20,000 per month from African Star Minerals, which funds its Canadian corporate operations. This amount is not directly tied to monthly sales, but is supported by African Star’s 20% 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, P.Geo., Executive Chairman of Southstone Minerals, and a Qualified Person as defined by National Instrument 43-101 of the Canadian Securities Administrators.
ON BEHALF OF SOUTHSTONE MINERALS LIMITED
Terry L. Tucker, P.Geo.
Executive Chairman
For additional information, please contact Terry L. Tucker at info@southstoneminerals.com
Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release. Capitalized terms used herein that have not been defined have the same meanings ascribed in the policies of the TSX.V.
Forward Looking Statements Disclaimer
Certain statements in this release are forward-looking statements, which are statements that are not purely historical, including any statements regarding beliefs, plans, expectations, or intentions regarding the future. Forward looking statements in this news release include statements relating to the Company’s proposed production timeline, and the Company’s plans for future production from the Oena Diamond Mine. Forward-looking statements are often identified by terms such as “will”, “may”, “should”, “anticipate”, “expects” and similar expressions. All statements included in this news release, other than statements of historical fact, are forward-looking statements that involve risks and uncertainties. There can be no assurance that such statements will prove to be accurate and actual results, and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from the Company’s expectations include quality and quantity of any mineral deposits that may be located, the Company’s inability to obtain any necessary permits, consents or authorizations required for its activities, the Company’s inability to raise the necessary capital to be fully able to implement its business strategies, and other risks and uncertainties disclosed in the Company’s latest interim Management Discussion and Analysis filed with certain securities commissions in Canada.
Forward-looking statements regarding operational expectations are based on management’s assessment of current mining conditions, contractor performance, and geological characteristics of identified zones.
The reader is cautioned that assumptions used in the preparation of any forward-looking statements herein may prove to be incorrect. Events or circumstances may cause actual results to differ materially from those predicted, as a result of numerous known and unknown risks, uncertainties, and other factors, many of which are beyond the control of the Company. The reader is cautioned not to place undue reliance on any forward-looking information. Such information, although considered reasonable by management at the time of preparation, may prove to be incorrect, and actual results may differ materially from those anticipated. Forward-looking statements contained in this news release are expressly qualified by this cautionary statement. The forward-looking statements contained in this news release are made as of the date of this news release and the Company will update or revise publicly any of the included forward-looking statements as expressly required by Canadian securities law.
Figure 1 – Location of Mining Sections and Mining License Boundary, Oena Diamond Mine.
Photo 1 – Sandberg Special Size Diamonds that sold for more than USD $5,000 per carat:
(1) 23.31 carats sold for USD $339,277 or USD $14,553 per carat.
(2) 34.51 carats sold for USD $175,035 or USD $5,072 per carat.
(3) 23.36 carats sold for USD $120,888 or USD $5,175 per carat.
(4) 18.53 carats sold for USD $108,770 or USD $5,870 per carat.