Even though champagne is a light yellow color, champagne diamonds are Light Brown. Cognac is usually used to describe a diamond that is Orangish-Brown because cognac is a deep golden-orange color. Some grading labs may also describe brown stones as Fancy Yellowish-Brown, Fancy Light Brown, Fancy Intense Brown, etc.
Brown diamonds are the most common color variety of natural diamonds. To explain its color, several causes have been identified, including irradiation treatment, as well as nickel impurities; the Ar- gyle mine, with its 35 million carats (7,000 kg) of diamonds per year, makes about one third of global production of natural diamonds; 80% of Argyle diamonds are brown.[
Famous brown diamond
The Golden Jubilee Diamond is currently the largest cut diamond in the world. It was found in 1985 as a rough stone of 755.5 carats
(151 g) in the De Beers operated Premier mine in South Africa. The stone was cut into 545.67-carat and was purchased from De Beers by a group of businessmen led by Henry Ho of Thailand in 1995. The Golden Jubilee Diamond was named by King Bhumibol Adulyadej and given to him on occasion of his 50th coronation anniversary.