From Carly Wickell,
Your Guide to Jewelry / Accessories.
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Four major components are considered when determining a diamond's quality and value. They are known as the Four C's: color, clarity, cut, and carat weight. Understanding these four diamond characteristics and how they interact can help you select a diamond that suits your tastes and your pocketbook.

Judging Diamond Color

Diamonds are not all truly colorless, but it's the colorless, often called white, which are diamonds that other shades are judged against.

The Gemological Institute of America (GIA) has devised a set of guidelines to grade diamond color. The color of graded diamonds is compared to the color of control stones, preselected gems of a specific color.

Diamond Grading Procedure

• Graded diamonds must be loose stones, because the color diamonds in settings can be affected by the metal colors used in the mountings.

• Diamonds are placed table-down, pavilion-up and viewed with a 10X loupe.

• A lettering system from D to Z is used to identify the amount of color present in each diamond, with D awarded only to rare, totally colorless diamonds.

Diamond Color Grades

Colorless diamonds and diamonds that are yellow or yellowish brown are grouped into the categories shown below. These grades do not apply to fancy colored diamonds--they have their own color grading standards.

D-E-F
Colorless.

G-H-I-J
Nearly colorless.

K-L-M
Faintly tinted, usually yellow.

N-O-P-Q-R
Lightly tinted, usually yellow. Tint can be seen with the naked eye.

S-T-U-V-W-X-Y-Z
Tinted, usually yellow, may progress to brownish. Tint visible to the naked eye, even when mounted.

Other Factors Affect Diamond Color

Fluorescence
GIA diamond reports and many other lab reports indicate whether or not a diamond exhibits fluorescence, which means the diamond's color changes when it is exposed to ultraviolet radiation. Since UV radiation is a component of daylight and is also present in fluorescent lit rooms, diamonds with this characteristic can appear to change color quite often.

• Diamonds that produce a blue reaction usually appear whiter, or more colorless, under UV light.

• Stones that fluoresce yellow appear even more yellow under some lighting conditions.

Diamond Color Treatments

The color of a some diamonds can be dramatically changed by using HPHT (high pressure/high temperature) processing. Unlike diamond treatments used in the past, HPHT changes appear to be permanent.

Coatings are sometimes used to temporarily enhance a diamond's color.

Choose Settings that Enhance Diamond Color

A loose diamond that appears lightly yellow to the naked eye will usually appear more colorless when mounted in a white setting--platinum or white-gold. Mounting the same diamond in yellow-gold metal usually enhances the diamond's yellowish tone.

Summing Up Diamond Color

A diamond's color grade affects its price, but it isn't the most important diamond characteristic to consider before purchasing a diamond. If your budget prevents you from buying a D through F graded diamond it does not mean you can't own a beautiful gemstone.

Diamond grades G through J can be fine gems and other grades may be perfectly suitable. An experienced jeweler can help you evaluate and select the best diamond for your needs.