London — Gem Diamonds has discovered two huge diamonds, each bigger than 100 carats, at its Lesotho mine. It unearthed the 117 carat and 110 carat D colour type IIa diamonds at the Letseng mine, Gem said in a statement on Monday. Type IIa diamonds contain very little or no nitrogen atoms and are the most expensive stones. The company’s stock rose as much as 8.2% in London trading. It’s a good start to the year following Gem’s discovery of at least seven stones bigger than 100 carats in 2017 and five the year before. It recovered a dozen diamonds bigger than 100 carats in 2015. Still, recent finds do not compare with the largest at Letseng, renowned for the quality and size of its stones. Gem sold a 357-carat stone for $19.3m in 2015 and in 2006 found the 603-carat Lesotho Promise. Lucapa Diamond also had a good new year, announcing on Monday that it had discovered 103 carat and 83 carat diamonds at its operations in Angola. The company’s biggest find to date was a 404 carat stone th...

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