by Staff Writer
Fine jewelry, especially if it features diamonds, is an investment that can last for generations, so it is important to know how to buy diamonds when shopping for these treasured gems. When purchasing diamond jewelry, pay attention to the diamond's four C's: color, clarity, cut, and carat weight. These are the four characteristics by which a diamond's quality is measured. If all four are ranked high, the diamond jewelry will cost more, but it will be that much more beautiful and valuable.
Diamond color: Traditionally, diamond color is actually graded on lack of color, and the best fine diamond jewelry contains stones that are almost clear. The hues graded in "white" diamonds are actually faint tones of yellow, brown and grey. An alphabetical scale from D through Z is used to rank the color. Imagine two glasses of water -- one clear, the other containing a few drops of lemonade -- and you will begin to get an idea of the differences in diamond color grades. The following color scale is an approximate representation of color saturation in diamonds:
G-I: Near colorless
J-K: Faint color
L-R: Noticeable color
S-Z: Obvious color
Fancy color: Once the color saturation moves beyond Z or has a completely different hue than yellow, brown or grey, the gem then becomes a fancy color diamond. Fancy colors are graded on how much color the diamond has and how strong the hue is. Diamonds come in every color of the rainbow, including blue, pink, yellow, purple and black. In general, fancy diamonds are rarer than white diamonds.
Black diamonds: Naturally black diamonds exist, but most of the stones used in jewelry design are lighter diamonds that have been treated to improve their color. The treatment, usually radiation or intense heat, darkens a diamond's color, making it appear black to the naked eye. Some of the treated diamonds are dark green, which you can see under magnification.
Diamond clarity: Clarity is the grade that describes the inclusions and blemishes of the diamond. The fewer inclusions and blemishes a diamond has, the more valuable it is. Clarity can also have a direct impact on the stone's brilliance. Inclusions in the diamond can block the light from reflecting inside the stone, which is the feature that gives diamond jewelry its fiery beauty. The following diamond clarity grades are listed from best to least and are based on the observations of trained gemologists:
FL (flawless): No inclusions or blemishes of any kind are visible inside or outside the diamond under 10-power magnification.
IF (internally flawless): The diamond has no internal inclusions when seen under 10-power magnification, but has some external or surface blemishes, such as miniscule scratches.
VVS-1 & 2 (very, very slightly included): The diamond has inclusions so minute that a trained gemologist has significant difficulty seeing them under 10-power magnification.
VS-1 & 2 (very slightly included): The diamond has minor inclusions, which are moderately difficult to see under 10-power magnification.
SI-1 & 2 (slightly included): The diamond has inclusions that are somewhat easily seen with 10-power magnification but extremely difficult for the gemologist to see without magnification.
SI-3 (slightly included): This rating is for stones that fall right on the border between SI-2 and I-1.
I-1, 2 & 3 (included): The diamond has inclusions that are noticeable without magnification.
Diamond cut: Cut is divided into shape, proportion, polish and symmetry. Shape and proportion are all of great importance when cutting a diamond to its best appearance. Shape and proportion determine how a diamond scintillates because it affects how light is reflected and refracted inside the stone, which is what causes diamonds to sparkle. Depending on how deep or shallow the diamond is cut, the face-up appearance of the diamond can also vary greatly. The polish describes how well light enters and exits the facets of the diamond. Symmetry can describe both length-to-width ratio and also depth percentages. Round-brilliant, princess-cut and emerald-cut diamonds are a few of the most popular diamond shapes.
Diamond carat weight: Carat is a weight measurement of diamonds. One carat is equal to 0.2 grams. It is abbreviated "ct" or "CT" when describing a single stone. "TDW," meaning "total diamond weight," is added when the diamond jewelry is set with multiple diamonds. For example, a solitaire diamond engagement ring may be described as 1ct while a three-stone diamond anniversary ring would be 1ct TDW.
Carat vs. karat: Carat is not the measure of gold's purity, which is spelled "karat" and is abbreviated "k." You may have a 1-carat diamond in an 18-karat gold setting.
Electronic diamond testers often identify treated black diamonds as moissanites, causing concern to consumers who thought they had black diamonds. This can occur if the tester was designed to separate diamond from moissanite based on electro-conductivity. Moissanite stones are electro-conductive, but natural-color diamonds are not. However, color-treated black diamonds become electro-conductive during the process that enhances their color. As a result, jewelers sometimes mis-identify the color-treated stones.
So how do you determine if a black diamond is a real diamond or a moissanite? Actually, the test that labeled the diamond as a moissanite reveals the gem's true identity. Although diamond testers identify colorless moissanite, they don't take accurate readings of any colored moissanite. Because neither natural-color black diamond nor black moissanite test as moissanite on the electronic testers, when a jeweler tests a stone and the tester indicates "moissanite," the test is a confirmation that the black gem in question is a treated-black color, natural diamond.
At the Tucson Gem Show in February 2012, the testing methods to distinguish black diamond from black moissanite were confirmed during educational sessions with renowned gemologist and author Antoinette Matlins.