Image: Okavango Diamond Company Botswana

Okavango Diamond Company (ODC) has revealed a 20-carat polished stone, the largest blue diamond to come out of Botswana.

The Gemological Institute of America (GIA) has graded the oval brilliant-cut, type IIb diamond as fancy deep blue, with VVS2 clarity, ODC said.

“From the first moment we saw the diamond, it was clear we had something very special,” Marcus ter Haar, managing director of ODC, said Wednesday. “Everyone who has viewed the 20-carat polished diamond has marveled at its unique coloration, which many see as unlike any blue stone they have seen before. It is incredibly unusual for a stone of this color and nature to have come from Botswana — a once-in-a-lifetime find, which is about as rare as a star in the Milky Way.

The 20.46-carat stone — cut from a 41.11-carat rough — was recovered from the Orapa mine, belonging to Debswana, a joint venture between De Beers and the government of Botswana. ODC, based in Gaborone, has access to 15% of Debswana’s run-of-mine production.

The Okavango Blue, named after Botswana World Heritage site, the Okavango Delta, will be showcased over the coming months before going up for sale at the end of the year.