Miner finds a rare 442-carat diamond that may be worth $18 million

Given the rarity of such large stones, demand for big diamonds has traditionally been resilient, even at times when the wider industry has struggled

A small diamond miner that has dug some of the world’s most valuable gems from a mountainous African kingdom has found another huge stone.

Gem Diamonds Ltd. said Friday it had an unearthed a 442-carat diamond at its Letseng mine in Lesotho. While it’s hard to establish a price for such stones before cutters can evaluate them, it could sell for as much as $18 million, Edward Sterck, analyst at BMO Capital Markets, wrote in a note.

Given the rarity of such large stones, demand for big diamonds has traditionally been resilient, even at times when the wider industry has