Unlike both the Constellation and the Lesedi, however, it is covered in carbon (at the moment it looks like a big lump of coal), which makes exactly what kind of diamond material is inside a “mystery,” according to Ulrika D’Haenens-Johansson, a senior research scientist at the Gemological Institute of America. It also makes “the risk that much greater,” Mr. Pruwer said. When the stone was unearthed, there was a fair amount of speculation that it may be worth significantly less than its not-quite-as-giant siblings. They can reveal when the diamond was created and at what depth in the earth. “Is it D or D-flawless, and how big is the flawless part?

Source: International New York Times January 15, 2020 22:52 UTC