What do you do when the majority of diamonds that you find in your mine are large, clear, and brown? You use the best and most beautiful of them as high quality gemstones, and sell them as champagne and cognac diamonds. These lovely diamonds are sold in bracelets, necklaces, watches and rings at retailers such as Macy's and specialty jewelers.
The Argyle Diamond Mine is located in the Kimberly region of Australia, and is the largest diamond producer in the world by volume. 90% to 95% of the world's supply of pink diamonds is supplied by the Argyle mine. Unfortunately, a large proportion of the rest of the diamonds from the mine are not standard gem quality. Most of the gem quality diamond production from the mine is in brown diamonds (80% of all diamonds from the mine are brown). Long seen as inferior diamonds, the Rio Tinto company has been promoting the brown diamonds as champagne and cognac diamonds, with marked success. Brown diamonds are also found elsewhere in the world, such as Africa and the United States in Arkansas.
The brown diamonds, or champagne and cognac diamonds, are large clear diamonds in shades of pastel brown, ranging from cinnamon (a pinkish-orangeish brown) to a pure brown, or dark-brown ranging from a cognac color to an olive-brown color. The pastels are referred to as champagne diamonds, and the dark browns are referred to as cognac diamonds. The color comes from the deformation of the lattice structure while the diamond is formed from heat and pressure, and trace amounts of impurities. Some yellow diamonds have a brownish shade to them, and are categorized as either yellow or brown diamonds.
Diamonds are graded using a rating scale of color, clarity, carat (size), and cut, also known as the 4 Cs. Brown diamonds are graded similarly to white diamonds, with the exception of color and cut. The Argyle Diamond mine has created the C1 to C7 color scale to grade champagne diamonds. C1 to C2 is the lightest brown color, and C5 to C6 is the darkest brown of the champagne diamonds. C7 is used for the darkest, richest brown of the cognac diamonds. The three aspects of color that are used in grading are hue, tone, and saturation.
Hue is the dominant color of the diamond, although secondary colors or tints can change the hue. Tone is the amount of lightness or darkness in the diamond, ranging from light to dark. Saturation is the intensity of the color of the diamond, from pastels to intense vivid colors. The more intense and vivid the color, the rarer and more valuable the diamond.
Colored diamonds are cut differently than white diamonds. White diamonds are cut to accentuate the brilliance of the stone and reflect the light most brilliantly. Colored diamonds are cut to accentuate the color and clarity of the stone, and are cut so that the color saturation is emphasized, and the size and brilliance is secondary.
Famous brown diamonds include:
- Incomparable is a 407.48 carat deep brownish-yellow diamond, internally flawless and the third largest diamond in the world
- The Golden Jubilee is a 545.67 carat fancy golden-brown diamond and is the largest faceted diamond in the world
- Ashberg is a 102.48 carat amber colored diamond and was formerly part of the Russian Crown Jewels.
- Earth Star is a 111.59 carat (cut, 248.9 carat rough) cognac diamond that was found in South Africa
- Great Chrysanthemum is a 104.15 carat brilliant orange-brown diamond that was cut into a pear shape to bring out the brilliance of the diamond
- Uncle Sam is a 12.42 carat (cut, 40.23 carat rough) pale-brown diamond, and is the largest diamond found in the United States, in the Arkansas Crater of Diamonds
- The Victoria-Transvaal Diamond is a 67.89 carat pear-shaped champagne diamond from South Africa, and was worn in 1952 in the movie Tarzan's Savage Fury.