The clarity of a diamond refers to how clear, or "clean" the diamond is. The more "clean" the diamond, the higher the price. Most diamonds have "imperfections" in them. The clarity scale is a measure of the severity of those imperfections or "inclusions" as it is known in the trade.
Both of these distinguishable features together are called clarity characteristics. A clarity grade is determined by the relative absence of clarity characteristics.
The following is the GIA Diamond clarity-scale:
(IF) INTERNALLY FLAWLESS
(VVS1 and VVS2) VERY VERY SLIGHTLY INCLUDED
(VS1 and VS2) VERY SLIGHTLY INCLUDED
(SI1 and SI2) SLIGHTLY INCLUDED
The Clarity Enhancement Process :
During the clarity enhancement process we insert a microscopic amount of material into the imperfection. This material has the same optical refraction index as the diamond. When light travels from one medium to another, it either changes its course or reflects in a different direction. When light attempts to pass through a non-enhanced diamond that has a feather, the light hits the feather and reflects in a number of directions. That is why we see the feather, and the diamond doesn't appear to be clean.
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