Gem Diamonds H1 2026 sales rise 33% as diamond prices strengthen

Gem Diamonds has delivered a stronger sales performance in the first half of 2026, despite processing a less valuable mix of ore and recovering fewer diamonds.

The operator of the Letšeng mine reported a 33% increase in total sales value to US$59.5 million. The average price achieved climbed 38% to US$1,395 per carat, more than offsetting a 4% reduction in carats sold.

That is the central message for investors. Production weakened as expected because mining was weighted towards the lower-grade, lower-value Main Pipe, but improved diamond prices and several exceptional stones protected revenue.

You can read the original H1 2026 company announcement for the full operational statement.

Gem Diamonds' key H1 2026 figures

Metric	H1 2026	H1 2025	Change
Waste tonnes stripped	308,118	1,698,817	-82%
Ore tonnes treated	2,604,145	2,504,001	4%
Satellite Pipe contribution	417,734 tonnes	802,135 tonnes	-48%
Carats recovered	41,695	47,125	-12%
Recovered grade	1.60 cpht	1.88 cpht	-15%
Carats sold	42,624	44,360	-4%
Total sales value	US$59.5 million	US$44.7 million	33%
Average price	US$1,395 per carat	US$1,008 per carat	38%

The company said all operational and financial measures were trending within its issued 2026 guidance. However, the announcement did not repeat the specific guidance ranges or provide cash, debt, costs or profitability figures.

Stronger pricing did the heavy lifting

Gem Diamonds sold fewer carats than it did during the same period last year, but generated significantly more revenue.

The 38% rise in average price per carat was therefore the standout number. It lifted total sales value by 33%, even though carats sold declined by 4% to 42,624.

Management said demand for Letšeng's exceptional-quality and large diamonds remained encouragingly strong. This appears to have helped the mine perform more resiliently than producers focused on smaller and lower-quality rough diamonds.

Eight diamonds sold for more than US$1.0 million each during the period, generating combined revenue of US$16.1 million. The highest price achieved was US$32,908 per carat for a 52.24-carat white diamond.

These sales demonstrate the value that a relatively small number of exceptional stones can contribute. They also highlight an important feature of the Gem Diamonds investment case: results can be heavily influenced by the timing, quality and sale prices of individual large diamonds.

Lower grade reflects the planned ore mix

The weaker production figures need to be viewed in the context of the mine plan.

Gem Diamonds processed 2.6 million tonnes of ore, 4% more than in H1 2025. However, recovered carats fell 12% and the recovered grade declined 15% to 1.60 carats per hundred tonnes, or cpht.

The reason was the lower contribution from the Satellite Pipe, which contains higher-grade and higher-value material. Satellite Pipe ore contributed 417,734 tonnes during the period, down 48% from 802,135 tonnes a year earlier.

Production was instead primarily sourced from the lower-grade, lower-value Main Pipe. This reduced the overall grade and the number of carats recovered.

That distinction matters. The production decline was not presented as an unexpected operational breakdown. It reflected the planned mix of material being treated. Nevertheless, a planned decline still affects the volume and potential value of diamonds available for sale.

The Lesotho Jubilee adds interest for H2

Three diamonds weighing more than 100 carats were recovered during H1 2026, although only two were sold within the reporting period.

The third was a 346.99-carat white diamond recovered in June. It has been named the Lesotho Jubilee to commemorate the 60th anniversary of Lesotho's independence on 4 October 2026.

The stone is due to be sold after the period end. Its eventual sale price was not disclosed, meaning none of that potential revenue is included in the US$59.5 million H1 sales figure.

This gives the second-half sales performance an additional point of interest. A strong price could make a meaningful contribution, but investors should avoid assuming a value before the sale takes place. Large stones are unusual assets, and their prices depend on individual quality characteristics and buyer demand.

Synthetic diamonds remain an industry pressure

Chief executive Clifford Elphick said market prices for lower-quality, small rough diamonds remained severely affected by synthetic diamonds.

Synthetic diamonds are laboratory-grown stones with the same basic material composition as mined diamonds. Their increasing availability can place pressure on prices in parts of the natural diamond market, particularly among smaller and more standardised stones.

Gem Diamonds said this pressure had contributed to several mines with that type of production profile suspending operations. Letšeng has been less affected because it is known for large, exceptional white diamonds, although it is not completely insulated from conditions across the wider diamond market.

Management's comments suggest the difference between premium and lower-quality rough diamonds remains important. Letšeng's product mix provided some protection during H1, but demand and pricing can still fluctuate.

What investors should watch next

The main operational challenge is that production for the rest of 2026 will come only from the Main Pipe while preparations are made for the next Satellite Pipe cutback.

That means the lower-grade and lower-value production mix seen during H1 is likely to remain relevant in the second half. The RNS did not disclose when material from the next Satellite Pipe cutback would begin contributing to production.

Key areas to monitor include:

• The sale price achieved for the 346.99-carat Lesotho Jubilee diamond.
• Whether average pricing remains strong enough to offset lower grades and carat recovery.
• Progress on preparations for the next Satellite Pipe cutback.
• Whether Gem Diamonds remains within its full-year operational and financial guidance.
• Any future disclosure on costs, cash generation and the balance sheet, which were not included in this update.

Investors may also want to compare the latest figures with the company's earlier operational and guidance update.

Premium stones offset the production decline

Gem Diamonds' H1 2026 update is encouraging on sales value but mixed operationally.

The positive is clear: stronger demand and pricing for Letšeng's premium diamonds lifted revenue despite fewer carats being recovered and sold. The company also remains on track against its issued 2026 guidance, according to management.

The less comfortable part is the production outlook. Mining will rely solely on the lower-grade Main Pipe for the remainder of the year, while revenue remains sensitive to the recovery and sale of a relatively small number of high-value diamonds.

For now, pricing has more than compensated for weaker volumes. Whether that balance continues through H2, alongside the Lesotho Jubilee sale, will be the key test.