A model poses with a vivid yellow 100.09 carats diamond during an auction preview at Sotheby's in Geneva
A model poses with a vivid yellow 100.09 carats diamond during an auction preview at Sotheby's in Geneva May 7, 2014. This item is expected to reach between CHF 13,250,000 to 22,250,000 (USD 15,000,000 to 25,000,000) when it goes on sale May 13, 2014 in Geneva. REUTERS/Denis Balibouse

One of the world's rarest gems, a rare blue flawless 12-carat diamond called the 'Blue Moon Diamond', has been adding a vibrant sparkle to the National History Museum's gem collection in Los Angeles since Sep. 12.

According to MyNextFone.co.uk, the 'Blue Moon Diamond' was bought in its uncut form at a price of $25.6 million($864,865 per carat) by Cora International, diamond manufacturers, in February. They have loaned it to the Los Angeles museum until January 2015.

The diamond is a 29.6 carat that was recovered by Petra Diamonds at the Cullinan mine in South Africa.

It is being considered an extremely significant find as it has a unique colour, clarity, size and is flawless internally with absolutely no inclusions.

Chief Executive Officer of Cora International, Suzette Gomes, said that many different vivid blues have been seen but this particular blue was an absolutely phenomenal colour and that she had never seen a colour like this before. She added that the Blue Moon Diamond is one of the rarest gems to be foung especially because of its colour and size.

The name of the diamond, 'Blue Moon Diamond', reflects on the diamond itself as such a diamond is found once in a blue moon.

Many scientists have raised geological questions about the origin of the stone.

A mineral science, curator and diamond expert at the Natural History Museum, Eloise Gaillou, said "Blue diamonds are among the rarest of all natural coloured diamonds. The exhibit will provide a once-in-a-lifetime opportunity for visitors to see one of the world's most exquisite blue diamonds in person."

She continued that the diamonds have come from 145 kilometres below the surface of the Earth, which provides some information about the happenings in the Earth's mantle.

She added that the origin of the blue colour is boron that isn't associated with the depth inside the Earth. Since blue diamonds are rare, this particular gem is going to provide the scientists information about the 'why, how and when as well', Eloise said.

Currently, the mineral collection at the Natural History Museum has about three thousand gemstones from almost a hundred and fifty thousand specimens of rocks, minerals, meteorites, of which many are from California.