Golden Jubilee Diamond

Golden Jubilee Diamond

The world's largest cut and faceted diamond.
Weight	545.67 carats (109.134 g)
Color	Unnamed Brown
Cut	fire rose cushion cut
Mine of origin	Premier Mine
Discovered	1985
Cut by	Gabriel Tolkowsky
Original owner	Henry Ho
Owner	King of Thailand
Estimated value	USD $4-12 million

The Golden Jubilee Diamond (Thai: เพชรกาญจนาภิเษก) is the largest cut and faceted diamond in the world. It weighs 545.67 carats (109.13 g). It outweighs the Cullinan I by 15.37 carats (3.07 g). The Golden Jubilee Diamond was discovered in the Premier Mine, which is also the origin of the Cullinan diamond (1905) and other notables such as the Taylor–Burton (1966) and the Centenary (1986). The Cullinan I, also known as the Great Star of Africa, had held the title of the largest cut and faceted diamond since 1908.

The diamond is valued at 4–12 million U.S. dollars.

The Golden Jubilee Diamond was cut from a large brown diamond of 755.5 carats (151 g), found in the prolific blue ground of the Premier Mine in South Africa in 1985. First known as the "Unnamed Brown," the Golden Jubilee was given to Gabriel Tolkowsky by De Beers for the purpose of testing special tools and cutting methods that had been developed for use on the colourless D-colour Centenary.

Because of its deep cracks and several inclusions, the Golden Jubilee Diamond was cut in a specially designed underground room free from vibrations. The yellow-brown diamond was transformed through a fire rose cushion cut. Until 1990, the diamond remained largely unknown to the outside world, requiring two years to bring it to its current state.

The unnamed diamond was brought to Thailand by the Thai Diamond Manufacturers Association to be exhibited in the Thai Board of Investment Exhibition in Laem Chabang and was selected to herald De Beer's centennial celebrations in 1988.

The Golden Jubilee was purchased from De Beers by a group led by Henry Ho in 1995. De Beers considered this as an opportunity to test new cutting technologies. The same technology used in cutting the future Golden Jubilee diamond was later used in the cutting of the Centenary Diamond, a smaller (273.85 carats) but much more obviously beautiful, flawless and colorless rough diamond.