Diamond colors is valued by what you can't see. The nearer they approach colorless, the more valuable they are (with the exception of fancy-color diamonds such as pink or blue).
The scale begins with the letter D, representing colorless and increasing to Z with the increasing presence of color. Diamonds are color-graded by comparing them to a known color under controlled lighting. These color distinctions are so subtle they are invisible to the untrained eye, but make a big difference in diamond quality and price.
Color grades apply to white diamonds. A clear diamond will reflect light in much the same way as a prism, dividing the light ray up into various areas of the color spectrum. This effect is what is referred to as "fire." The presence of color in a diamond will decrease the intensity of the stone's "dispersion" or "fire." Similarly diamonds with little to no color will display the most intense "fire." Diamond color is graded along an alphabetical scale starting with "D," as follows: D, E, F
Colorless: Diamonds which are graded D, E, or F are considered colorless, and are the most rare and expensive.
G & H
Near Colorless: Diamonds which are graded either G or H are considered near colorless. These stones in particular contain so little color that it is barely noticeable to the naked eye.
I & J
Near Colorless: Diamonds which are graded either I or J are also considered near colorless. These stones have a slight amount of color which may be evident to the naked eye.
The color is noticeable especially in smaller stones.
Fancy Diamond Colors
Four Cs of Fancy Color Diamonds
Like other diamonds, the price of a color diamond depends in part on the Four Cs: color, cut, clarity and carat weight, but the factors used to judge those qualities differ somewhat from the Four Cs of colorless diamonds.
Fancy color diamonds are graded in two ways. The first factor considered is the stone's basic hue, such as pink, yellow, blue, green, etc. The second is the diamond's intensity. Both color characteristics form the basis for determining a fancy colored diamond's worth.
Usually, the more intense the color, the rarer and more expensive the diamond will be. For example, a fancy light pink diamond costs less than a fancy vivid pink diamond of equal size, shape and clarity.
Scale of diamond color saturation
The GIA uses nine categories to grade color diamonds.
- Very Light
- Fancy Light
- Fancy Dark
- Fancy Intense
- Fancy Deep
- Fancy Vivid
A secondary undertone that enhances the color of a diamond is a plus. A secondary that detracts from the color is a negative. For instance:
Purplish pink color diamond can be worth more than a pink diamond, depending on the amount and intensity of purple
Prownish tint in a pink diamond usually decreases its value, and makes it a more affordable gemstone
|Fancy Brownish Pink
||Fancy Intense Pinkish Orange
||Fancy Purplish Pink
||Fancy Intense Pink
|Fancy Intense Yellow
||Fancy Green Blue
|Fancy Deep Greenish Blue
||Fancy Intense Blue
||Fancy Vivid Blue
||Fancy Blue Gray
Color Diamond Cut & Shape
Like other diamonds, fancy colored diamonds achieve maximum brilliance when cut to the most ideal and accurate proportions. A good cut gives a fancy diamond its sparkle and helps to bring out the most intense color possible.
When cutting color diamonds, the cutter usually considers its inclusions, because they can enhance the diamond's color. Facets and angles also add color to a diamond, so the cutter must think about what shape would bring out the gemstone's best appearance.
Due to the rarity, it may only be possible to find a smaller colored diamond, which can be set beautifully with imagination.
Sometimes, a lighter stone can be set in the same color metal to increase the intensity of the color. A light Pink may be set in a pink gold cage or a yellow diamond may be set in a yellow gold cage, while the rest of the ring, the microset pave diamonds and the shank, are white gold or platinum.
|Fancy Purplish Pink in a pink gold setting
||Light Yellow in a yellow gold setting on Platinum
Black Diamonds are sometimes used as the large major stone, but more often than not, they are used to highlight lighter color stones and are usually set in gold that has been plated with black rhodium to deepen their appearance.
Coatings & Other Color Tricks
Coatings applied to change a diamond's color are not permanent and are nearly always done to deceive the buyer.
Diamonds are sometimes coated with a substance that masks yellowish tints. Though it is applied with heat, the coating will eventually rub off with normal wear and cleaning.
Sometimes dots or larger areas of purple or blue ink are painted on the diamond to help counteract a yellowish color. The dots are usually obscured by the diamond's setting, so they are difficult to see in a mounted stone. The coating can usually be removed with water or cleaning solutions.
Creating Colorful Diamonds
Irradiation, followed by a high heat treatment, can turn brown and yellow diamonds into fancy colored diamonds--greens, vivid yellows, blues, purples, reds and other colors. The color is usually permanent, but could possibly change if high heat is used during setting repairs.
Natural fancy colored diamonds are expensive and out of the reach of most buyers. A certificate from a respected grading lab should accompany all fancy colored diamonds that are marketed as natural.
Question the ethics of anyone who attempts to sell you a natural fancy colored diamond for a bargain price.
Treatment-produced fancy colors are affordable, and allow more of us to own a brightly colored diamond. They should not be considered an investment. Buy one because you love it, not because you think you can sell it for a profit later.
Ask the jeweler for care instructions when you buy an irradiated fancy color diamond.
High Pressure High Temperature Treatment (HPHT)
HPHT was first used to turn yellowish diamonds into fancy colored diamonds, but now it is also used to transform some unpopular brownish diamonds into more expensive colorless diamonds.
Some companies claim HPHT isn't a treatment at all, calling it a technique that finishes the job nature started. That attitude, and the fact that the process is difficult to detect, has made HPHT a controversial topic.
General Electric is producing colorless diamonds, called Bellataire, from type IIa diamonds that are nitrogen-free. The company has applied for a patent on the process used to transform the stones. On their Bellataire Web site, GE states:
"BELLATAIRE Diamonds are extremely rare Type IIa diamonds that were originally crystallized without color and were destined to become extraordinary gems. During their journey to the surface of the Earth through volcanic pipes, though, these crystals were subjected to intense heat, tremendous pressure, and explosive turbulence. These conditions caused some molecular misalignment in these crystals, resulting in a brownish color and internal stress."
GE's position is that the process they use restores diamonds to their colorless state.
Gemological Institute of America (GIA) grading reports now indicate when HTPT treatments are detected by stating "HPHT Annealed" or "Artificially Irradiated" in the Origins portion of a report.
Only diamonds that are laser-inscribed with the words "HPHT PROCESSED," "IRRADIATED," or a specific registered name are graded.
GE uses a registration number and the letters "GE POL" to inscribe their diamonds.
There have been instances where inscribed lettering has been removed before a diamond was submitted for grading.
HPHT will continue to be a controversial topic, with grading labs trying to perfect ways to detect the always-improving process so that consumers can receive full disclosure about the diamonds they purchase.
Should you purchase an HPHT diamond? You're the only one who can make that decision. The diamonds are definitely gorgeous, but choosing between altered and natural is a personal decision.
A few facts about HPHT Diamonds:
- HPHT is permanent.
- The Federal Trade Commission (FTC) requires that HPHT be disclosed.
- Most HPHT diamonds weigh over 1/2 carat.
- HPHT diamonds should cost less than similar natural diamonds.