As well as one “significant” single polished stone, there’ll be other offcut pieces as large as 20 to 30 carats each worth millions of dollars, Lamb said. The Lesotho Promise produced 26 flawless diamonds, including a 76.4-carat pear- shaped gem.
Luck also played a role. The company may never have caught the diamond if it didn’t recently increase the size of the holes at its plant that lets gems drop through instead of being smashed along with rock dug from the ground. Lucara can now catch gems as big as 1,800 carats and needs to decide whether its worth investing in expanding the capacity to 3,000 carats.
Will there be more 1,000-carat-plus stones?
“There’s no real statistical numbers you can run on this,” said Lamb. “It’s an absolute anomaly. It’s too far off the curve.”