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.
The Argyle Diamond Mine was a diamond mine located in the East Kimberley region in the remote north of Western Australia. Argyle was at times the largest diamond producer in the world by volume, although the proportion of gem-quality diamonds was low. It was the only known significant source of pink and red diamonds, and additionally provided a large proportion of other naturally coloured diamonds, including champagne, cognac and rare blue diamonds.
The open pit of the Argyle diamond mine. A large mining truck is visible on the road for scale.
Uncut diamond crystal from the Argyle mine, 4.27 carats
A large brown Argyle diamond, 3.6 carats
Aerial view of the open pit in 2007
