Brown diamonds

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 significant portion of the output of Australian diamond mines is brown stones. There are several causes for the brown color, including irradiation treatment, nickel impurities and lattice defects associated with plastic deformation; the last is the predominant cause, especially in pure diamonds. A high-pressure high-temperature treatment can heal lattice defects and convert brown diamonds into yellow or even colorless stones.