What’s more, because black diamonds are opaque – and, in most cases, heavily included – they cannot be graded on the GIA clarity scale. Black diamonds fall outside this color range, so their color is evaluated based on GIA’s color grading system for colored diamonds. The 4Cs – color, clarity, cut and carat weight – together with GIA’s International Diamond Grading System TM are the standards by which colorless to near-colorless (D-to-Z color diamonds) are graded. Courtesy: Front Jewelers, How Are Black Diamonds Graded? Artificial irradiation of off-color diamonds can also produce a green so dark the diamond appears black.Ī 2.01 ct princess cut black diamond set in 14K blackened gold with black diamond side stones is the definition of a statement engagement ring. Many begin as gray, heavily included and fractured diamonds that are subjected to high-temperature/low-pressure treatment, which graphitizes the fractures, turning them black. Most of the black diamonds sold for jewelry and engagement rings have been treated to induce the color. They are often more affordable than other diamonds, too. However, a fine natural-color black diamond is a beautiful stone, with a distinctive look unlike other diamonds in the marketplace. Natural-color black diamonds typically are completely opaque, with a high luster that gives the stones an almost metallic appearance. And because these diamonds are so heavily included, cutting and polishing them can be difficult. In fact, the actual body color of a natural black diamond may range from near-colorless to brown or “olive” green. It is the concentrations of these internal features that are responsible for the coloration. These diamonds may also have numerous cleavages or fractures that are stained black or have become black because of graphitization. Today we know that most naturally colored black diamonds get their color from large quantities or clouds of minute mineral inclusions such as graphite, pyrite or hematite that extend throughout the stone. Research into the cause of color in black diamonds is relatively recent. The two rubies and colorless diamond accent stones create vivid color contrasts. A 6.21 ct black diamond commands attention in this dramatic ring.
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