Los Angeles County's Natural History Museum unveiled on Friday, Sept. 12, a rare diamond that it will put up on display at its special Gem Vault exhibition which will start on Saturday until Jan. 6 next year.

The 12-carat gem called the "Blue Moon Diamond" is one of the rarest stones in the world because of its distinct color, size and clarity. The saturated blue-colored and intensely radiant stone was cut from a rough diamond that was found by miners in the Cullinan mine, which is located 40 kilometers east of Pretoria in South Africa, in January this year.

The Cullinan mine is known for producing notable and world-famous diamonds such as the 3,106-carat diamond that was unearthed by Premier Diamond Mining Company's surface manager Frederick Wells in January 1905.

The stone, which became known as the Cullinan diamond, was the largest diamond crystal ever found. It was presented to King Edward VII of Britain as a token of loyalty and was eventually cut up with the 530.4 carat "Great Star of Africa" and the 317.4 carat "Second Star of Africa" cut from the Cullinan stone. Both stones, which are among the biggest polished diamonds in the world, now form part of the British crown jewels and are currently housed at the Tower of London.

Blue Moon was cut from a 29.63-carat rough diamond, a process that took six months, and fashioned to form a cushion-cut shape. The value of the gem is not yet known but Cora International, a leading supplier and manufacturer of diamond, bought the rough diamond for $26 million, according to the chief executive of the company Suzette Gomes.

"After seeing the stone's color and understanding its significance, it was fitting to name it the Blue Moon Diamond as not only its shape is reminiscent of a full moon, but the metaphor for the expression is exactly what one could say about the occurrence and existence of such a gemstone," Gomes said. 

Cora bought the rough stone from Petra Diamonds Ltd., which owns the Cullinan mine since 2008, through Golden Yellow Diamonds, which is based in South Africa.

There are only a few big diamonds that exist including the "Heart of Eternity," which is valued at $16 million and the Hope diamond, a 45-carat stone notoriously known as the cursed diamond, which is estimated to value $350 million. Blue Moon is a 12.03 -carat stone, weighing 2.4 grams and measures 0.61 inch in its longest diameter.