The Golden Jubilee Diamond, a 545.67 carat brown diamond, is the largest cut and faceted diamond in the world. It outweighs the Cullinan I by 15.37 carats. The Golden Jubilee Diamond was discovered in 1985 at 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). Cullinan I, also known as the Great Star of Africa, had held the title of the largest cut and faceted diamond since 1908.
The world's largest cut and faceted diamond.
Brown diamonds are the most common color variety of natural diamonds. In most mines, brown diamonds account for 15% of production. The brown color makes them less attractive to some people as gemstones, and most are used for industrial purposes. However, improved marketing programs, especially in Australia and the United States, have resulted in brown diamonds becoming valued as gemstones and even referred to as chocolate diamonds.
A collection of brown diamonds in the National Museum of Natural History, Washington, D.C. The pear-shaped pendant at the bottom of the necklace weighs 67 carats (13.4 g).
Pure diamonds, before and after irradiation and annealing. Clockwise from left bottom: 1) Initial (2×2 mm) 2–4) Irradiated by different doses of 2-MeV electrons 5–6) Irradiated by different doses and annealed at 800 °C.