Gem Diamonds Limited (LSE: GEMD), the 70% owner of the Letšeng mine in Lesotho — recognised as the world's highest dollar-per-carat kimberlite diamond operation — has published its Q3 2026 trading update covering the period 1 July to 30 September 2026. The company reported Q3 revenue of US$34.8 million, up from US$25.7 million in Q3 2025, driven by the sale of the 347-carat Lesotho Jubilee white Type II diamond and three other stones each fetching more than US$1.0 million. Following strong operational performance and cost containment, the Group has positively revised its full-year 2026 guidance across several key metrics.

Key Points

  • Gem Diamonds Limited (LSE: GEMD), producer of high-value diamonds at the Letšeng mine in Lesotho
  • Q3 2026 revenue reached US$34.8 million at an average price of US$1,945 per carat, compared with US$1,124 per carat in Q3 2025
  • FY2026 carat recovery guidance revised upward to 78,000–80,000 carats; direct cash costs per tonne treated guided lower to 205–215 Maloti
  • Investors should watch the December 2026 revolving credit facility renewal and the new Lesotho variable royalty rate effective from 1 October 2026

Letšeng Mine Delivers US$34.8 Million Q3 Revenue as Average Price Climbs to US$1,945 per Carat

Gem Diamonds recovered 19,299 carats during Q3 2026, below the 22,268 carats recorded in Q3 2025, yet revenue rose materially year-on-year. The announcement states that 17,899 carats were sold in the period, generating US$34.8 million in revenue at an average of US$1,945 per carat. Four diamonds sold for more than US$1.0 million each, collectively contributing US$22.2 million to Q3 revenue. The standout transaction was the 347-carat Lesotho Jubilee — an exceptional white Type II diamond recovered in Q2 2026 — whose sale the company identifies as a key driver of the elevated per-carat pricing achieved during the quarter.

Six Greater-Than-100-Carat Diamonds Recovered Year to Date at Letšeng as Main Pipe Dominates Production

Three diamonds exceeding 100 carats were recovered during Q3 2026, bringing the year-to-date total for such stones to six. Production during the period was sourced primarily from the Main Pipe, with only 7,143 tonnes of remaining ore from the current Satellite Pit cutback processed. The announcement notes that preparations are continuing for the next Satellite Pipe cutback. The grade recovered in Q3 2026 was 1.42 carats per hundred tonnes, compared with 1.69 cpht in Q3 2025, reflecting the shift in ore source mix rather than any structural change to the deposit, the disclosure suggests.

Lesotho Government Approves Variable Royalty Rate of 3%–6% for Sales from 1 October 2026

A royalty remission granted to Letšeng Diamonds ran until the end of September 2026. Following the period, the Government of Lesotho approved a new variable royalty structure of between 3% and 6%, determined on a six-monthly average dollar-per-carat basis and effective for all sales from 1 October 2026. CEO Clifford Elphick described this as "a good policy decision ensuring the long-term sustainability of the mine." Investors may be watching whether the higher per-carat prices seen in Q3 2026 place the operation toward the upper end of the new royalty band in the first assessment period.

Gem Diamonds Revises FY2026 Guidance Higher and Progresses Nedbank and Standard Bank Facility Renewal

The Group positively revised its full-year 2026 guidance across multiple metrics. Carats recovered are now guided at 78,000–80,000, up from the original 75,000–78,000, while carats sold guidance moves to 79,000–81,000. Direct cash costs per tonne treated are guided lower at 205–215 Maloti against the original 220–235 Maloti range. Total capital expenditure guidance was also reduced markedly. Separately, the Group's revolving credit facilities expire on 21 December 2026; the announcement states that commercial terms and conditions are currently being finalised with Nedbank Limited and Standard Bank, representing a near-term refinancing milestone investors should monitor closely.