It’s only half true that diamonds are a girl’s best friend—just like people, only a few diamonds are worthy of your company and devotion. How can you choose the quality gems from the clunkers? Consult this quick, simple guide to diamond grading.
Cut is by far the most important of the 4 C’s. In the rough, diamonds look ordinary (and, if you can believe it, sometimes downright ugly). However, when cut by a highly-skilled expert jeweler, a diamond is shaped with a series of clean, sharp cuts that cause it to refract light and transform the stone into the valuable gem that we recognize as a diamond gem. a well-cut diamond will have sparkle and “fire” whereas a poorly cut one will appear dull, despite its relative clarity and colorlessness.
Diamonds range in color from absolutely colorless to visibly tinted with yellow. The GIA grades them on alphabetic scale of D-Z, with D being perfectly colorless and Z being pale yellow. Colorless diamonds are extremely rare and valuable, and diamonds rated J or higher look colorless without magnification. Colorlessness is valuable in diamonds because the lack of color allows light to scatter and create its scintillating, multicolored appearance.
A diamond’s color is complicated slightly by a quality called fluorescence. This refers to the color a diamond emits under fluorescent light. A diamond that is yellow in natural light but blue or white in fluorescent light will be deemed more valuable, while an apparently colorless diamond that has a yellow fluorescence will lose value.
Just like people, even the most gorgeous diamonds on the planet are unlikely to be free from a few flaws. In fact, flawless diamonds are nearly unheard-of, and most jewelers have never seen one. That being said, clarity still has an effect on a diamond’s value, and visible defects decrease the diamonds value considerably. Your best bet when buying a diamond is to obtain a clarity grading report, which maps visible and invisible inclusions within the gem.
Carat weight factors into a diamond’s value, but this category can be confusing. Carat refers to the weight of a diamond, but not necessarily its size. Furthermore, it’s not so much the size of the carat as what carat it is exactly that determines the diamond’s value. A diamond with a “magic” carat size of .5, .75 or 1 carat will be more valuable that a diamond of a similar weight that is not in the “sweet spot.” For example, a diamond that weighs .5 carats may be much more expensive than one that is .52!
Don’t prioritize diamond weight as the end-all be-all factor in your search for the perfect diamond. Finding a clear, expertly cut diamond should be higher on your checklist.