Unique 3 billion year blue diamond

Okavango, a 20.46 carat oval blue diamond among the world's rarest, was discovered at the Orapa mine in Botswana,

Okavango blue diamond after polishing. Photo: Okavango Diamond Company

Okavango blue diamonds are said to be formed at a depth of 668 km below the ground. At that depth, boron is uncommon, but the Okavango is full of the element. It has a higher proportion of boron than nitrogen, an element that is more common in the environment and usually makes up a large proportion of most diamonds, according to IFL Science .

"From the first moment we saw the diamond, we knew it was very special," said Marcus ter Haar, representative of the Okavango diamond company. "Everyone who saw the more than 20-carat diamond was amazed by its unique color, unlike the blue color of any gemstone ever found before. This is a unique discovery."

According to Okavango Diamond Company in Botswana, the unit that discovered the gem, in rough form, Okavango blue diamonds weigh 41.11 carats. After cutting and polishing, it is classified as "Fancy Deep Blue", one of the highest color classifications a blue diamond can achieve.

Blue diamonds like Okavango can only be found in a few mines around the world with a unique geological history. Diamonds are usually colorless due to the combination of carbon atoms, but impurities can give them different colors. Colored diamonds account for only 0.01%, or 1/10,000, of the diamonds mined on Earth. Among them, blue, pink, green, purple, orange and red are the rarest colors, yellow and brown are slightly more common.