Most Champagne diamonds come from the Argyle Mine in the remote East Kimberly region of Western Australia. They are close to the lower end of the value scale in comparison to other natural fancy diamonds because they are still quite abundant. However, industry experts believe that Champagne diamonds will likely follow the same ‘lucrative’ trajectory as Pink diamonds when the world’s largest producer of Champagne diamonds, the Argyle Mine closes in 2018.
Until recent years, Brown diamonds were only used for industrial purposes. They went from a zero to a 5 billion dollar industry in 5 short years. Today, Champagne diamonds are sold everywhere and are becoming the choice of many celebrities. Champagne Diamonds that receive a high clarity grade or contain pink or orange modifiers are considerably more valuable than those that don’t.
Characterization of Champagne (Brown) Diamonds
When someone describes a diamond as being “brown,” they are referring to the dominant color seen in that stone. “If you are looking through the side of a polished brown diamond (body color), this is referred to as inherent color variety of a diamond” says Stephen Hofer (Collecting and Classifying Colored Diamonds, 1998). However he shows if you are looking at the same diamond from a birds eye perspective (face up color), this is referred to as apparent color variety.
Brown diamonds are beautiful diamonds and industry writers have made various attempts to help the public understand the complexity of browns. The Rio Tinto Argyle Mine developed a simple grading scale based on visual comparison (C1, C2, C3, C4, C5, C6, C7). The seven grades are intended to distinguish between different (shades) of brown (Hofer, 1998).
This has been an important step in raising awareness and communicating the beauty of brown diamonds, however, for the avid collector it over simplifies the problem of differentiating brown diamonds (Hofer, 1998).
The problem in grading brown diamonds is that the region of ‘color’ that defines brown diamonds (the brown color space) is three-dimensional, more like a box, which covers a large lightness range including considerable variations in hue and saturation (Hofer, 1998).
Plastic deformation is the reason for the brownish color in Champagne (brown) diamonds and it refers to a change in the diamond’s molecular structure. Champagne diamonds contain low levels of nitrogen making them more susceptible to this deformation. Nitrogen is an impurity atom that cause yellow coloring in diamonds.
Natural color brown diamonds occur in four colored tone quadrants; pale, bright, dull and deep. Pale, dull and deep occur in nature more often than bright. That is because as browns lighten and saturate i.e. brighten they appear orange or yellow sometimes even pink or red (Hofer, 1998).
As noted above, Champagne diamonds are graded on a scale from C1 to C6. C1 is the lightest colour and C6 the most intense. C1 and C2 are light champagne, C3 and C4 medium champagne, and C5 and C6 dark champagne. Diamonds graded C7 exhibit the most intense, deep brown colour and are the most rare and expensive (Argyle: Past and Present). Dark brown diamonds that contain larger amounts of orange are referred to as Cognac.
A pure brown diamond with no secondary color is extremely rare and to find one with a certificate stating that it is pure brown is a special occurrence.
The color blue with brown creates unusual effects, which do not frequently occur in nature. But when it does, its florescence can look ‘oily blue’ (and/or green) (Hofer, 1998). Hofer explains that these are called color modifiers (1998). Color modifiers- also referred to as minor, subordinate or secondary hues.
Artificially Treated Brown Diamonds
Modern coloring methods (i.e. heating) can produce close replicas however they are not exact facsimiles. Most treated brown diamonds are saturated in tone and will appear artificial to the trained eye. Most of them exhibit orange like modifiers and sometimes yellow or red (Hofer, 1998).
Neutron-irradiated browns seem un-natural because the brown color appears as if the brown is masking the previous color (i.e. Yellow, gray, olive) resulting in a muddy brown diamond.
Artificially treated brown diamonds are not that common, however, pale brown diamonds that have undergone radiation treatment to look like blue diamonds are more common because the financial incentive is far greater (Hofer, 1998).
Famous Champagne Diamonds
The Golden Pelican is a large 63.93 carat pure brown rectangular Emerald Cut diamond named after the famous street in Antwerp 鑽石耳環款式 and was sold at Christies in 1974. The Golden Jubilee Diamond is the world largest brown diamond and weighs a total of 545.67 carats. It was given to the King of Thailand as a gift in 1997 as a gift for the 50th anniversary of his coronation. What’s most remarkable about the stone is its yellow brown color.
The most anticipated Brown diamond sale is Elizabeth Taylor’s 32.14 carat Cognac – fancy deep brownish orangey yellow VSI which will probably make a record on December 13, 2011. It is suspected to break world records.