Gem Diamonds shares jumped over 30% on strong 2025 production results, including a large diamond find, despite lower total output.

Gem Diamonds (LON:GEMD) shares rose over 30% on Wednesday, reaching a high of GBX 4.50, after strong 2025 production results met or exceeded guidance, including the recovery of 90,354 carats and a 193-carat white Type II diamond found post-year-end. The surge, accompanied by a significant spike in trading volume, followed a decline in total carat output compared to 2024. The company, which owns 70% of Lesotho’s high-value Letšeng mine, reported positive operational performance despite challenging earnings metrics. No specific cause for the price increase was confirmed.