These days, so many brides are opting for a colored diamond engagement ring. We went straight to the expert—John King, Chief Quality Office for the GIA [Gemological Institute of America]—and asked him three questions about these increasingly popular gems ...
Q: What makes a diamond a color, as opposed to white?
A: For different diamond colors there are different causes. For some colors, it is the substitution of trace elements for the carbon atoms in the atomic structure: nitrogen makes a diamond yellow; boron makes a diamond blue. In other cases, structural anomalies result during the diamond’s formation and affect how light is absorbed and transmitted. These can cause diamonds to appear pink or brown.
Above, left-to-right: Harry Winston "The One" cushion-cut yellow center stone with pavé diamonds set in platinum; Henri Daussi "R1-10" band of round irradiated blue diamonds set in white gold; De Beers "Aura" ring with fancy pink oval-cut solitaire and fancy pink micropavé band; Suzanne Kalan "Cluster" ring of round-cut champagne diamonds on a 14k rose gold band.
Q: We know about the 4Cs for grading white diamonds—cut, clarity, carat weight, and color. Are colored diamonds graded differently?
While the 4Cs still apply, the rarity of colored diamonds causes the “C” for color to outweigh the others of clarity, cut, and carat weight. A classic example of this is a diamond known as the Hancock Red. It weighs a little less than one carat [0.95 ct] and had inclusions visible to the eye. Yet the color is so rare it sold for almost a million dollars at auction in 1987. Most seasoned professionals in the diamond trade estimate that [only] one in 10,000 diamonds is a colored diamond.
Above: The Hancock Red Diamond, courtesy of GIA.edu.
Q: Is there a way to know that the color of a diamond is natural and not synthetic, created in a lab?
Yes. It requires sophisticated laboratory testing as is done by GIA. We've studied diamond origin of color throughout the Institute’s history, and GIA’s advanced analytical techniques ensure the consumer’s trust in this important determination. Make sure you see the GIA certificate before your purchase any stone.
Above: An sample GIA report on a yellow diamond.