The Cullinan Diamond
The Cullinan Diamond is rightly famous as the largest natural gem-quality diamond ever found. In its raw state it weighed in at a massive 3106 carats (621 gm, about 21 ounces).
History
The Cullinan was discovered in 1905 at the Premier Mines in South Africa. The discovery was made by a mine superintendent named Frederick Wells and was basically a lucky accident; Wells happened to glance up at the wall of the mine and noticed a huge lump of what he assumed to be glass! The stone was named after Sir Thomas Cullinan who owned the mine, although "The Wells Diamond" would have been a more accurate name.The stone was bought by the Transvaal government and given as a present to England's King Edward VII. It was then sent to Amsterdam where it was to be cut by the renowned Asscher brothers (from whom we get the Asscher cut). The brothers studied the stone for many months before daring to attempt to cut it - and at the first try it was the blade that fell apart rather than the diamond! It's said that for the second attempt Joseph Asscher had a doctor and nurse standing by - which proved a sensible precaution because when the stone split he immediately fainted.
Star of Africa
The Asschers eventually succeeded in cutting the raw Cullinan diamond into 105 finished gems of various sizes. The Most famous of the are Cullinan I and Cullinan II - known more romantically as the Greater and Lesser Star of Africa. These now form part of the Crown Jewels of England which are on display in the Tower of London.The Great Star of Africa has a mass of 530.2 carats (106 grams, just under 4 ounces) and at the time of cutting was the largest polished diamond in the world. This record was broken in 1985 by the discovery of the Golden Jubilee Diamond - which also came from the Premier mine.