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Diamond clarity is the quality of diamonds that relates to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects, called blemishes. Clarity is one of the four Cs of diamond grading, the others being carat, color, and cut.
When color grading is done in the mounting, the grade is expressed as an estimated color grade and commonly as a range of color. Grading mounted diamonds involves holding the mounted diamonds table close to the table facet of the master stone and visually comparing the diamond color under the same color conditions as unmounted diamond grading.
The grading scale of clear diamonds ranges from D to Z. D means there is no color at all, while Z means there is significant and noticeable color. For colored diamonds, a different scale exists.
A diamond simulant is a non-diamond material that is used to simulate the appearance of a diamond, and may be referred to as diamante. Cubic zirconia is the most common. The gemstone moissanite (silicon carbide) can be treated as a diamond simulant, though more costly to produce than cubic zirconia.
GIA was also responsible for the first modern diamond grading reports, where it introduced grading methodologies for diamond color and diamond clarity. Current research at gemological laboratories concerns the development of improved detection techniques for treated and synthetic diamonds , as well as for treated sapphires , rubies and pearls.
The GIA began grading cut on every grading report beginning in 2006, based on their comprehensive study of 20,000 proportions with 70,000 observations of 2,000 diamonds. [4] The single descriptive words are as follows: Excellent, Very Good, Good, Fair, and Poor. The distance from the viewer's eye to the diamond is important.
A diamond's cut is evaluated by trained graders, with higher grades given to stones whose symmetry and proportions most closely match the particular "ideal" used as a benchmark. The strictest standards are applied to the round brilliant; although its facet count is invariable, its proportions are not.
The quality of a diamond's cut is widely considered the most important of the four Cs in determining the beauty of a diamond; indeed, it is commonly acknowledged that a well-cut diamond can appear to be of greater carat weight, and have clarity and color appear to be of better grade than they actually are.
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