Diamond Grading is a process of recognizing the value of a diamond based on the standards provided by GIA. A diamond can be rated on a scale of 0 – 10. The best diamond has a rating of 0 and the worst at 10. Diamonds are rated based on 4Cs which are Color, Clarity, Carat Weight, and Cut Scale. A diamond’s value is often affected by the rareness of one or more of the four Cs.
Cut refers not to a diamond’s shape but to a diamond’s proportions, symmetry, and polish. The beauty of a diamond depends highly on the cut. A cut scale has the values distributed in a range from 0-10 in which0-1 is excellent,2 is very good,3-4 is good,5-7 is fair and 8-10 is poor.
Three optical effects that occur in the diamond show how the diamond interacts with light and create desirable visual effects. The white light reflected internally and externally from the diamond called brightness. The white light scatters into seven colors and making the rainbow which is called fire, and the reflection making pattern of light and dark areas due to which diamond produces sparkle is called scintillation. Approximately, 20% of light reflects off immediately after striking from the surface of the diamond. Of the 80% that enters, a portion will escape through the bottom of the diamond.
Clarity refers to the degree to which small imperfections also known as inclusion are present due to the formation of diamonds deep within the earth, under extreme heat and pressure. A clarity scale has the values distributed in the range of 0-10 in which 0 is flawless(IF),1-2 is very very slightly included(VVS),3-4 is very slightly included(VS),5-7 is slightly included(S) and 8-10 is included(I).
Flawless diamonds are very much rare, so rare that it’s possible for a person to spend a lifetime in the jewelry industry without ever seeing one, and they are priced the highest. If you are buying diamonds and cannot tolerate imperfections, even those you cannot see, choose a VVS2(2 on the scale) or better diamond. About 10% of all diamonds sold fall into this category. The most popular range is the VS1-VS2(3-4 on the scale) diamond. These diamonds appear flawless to the naked eye. Almost half of all diamond people purchase fall into this range.
Diamonds are available in a variety of colors. The yellowness of the diamond lowers its prize. A small presence can bring highly change in values of two diamonds having the same cut and same clarity. A color scale has the values distributed in the range of 0-10 in which 0-1 is colorless,1.5-3 is nearly colorless,3.5-4.5 is faint,5-7 is very light and 7.5-10 is light, and after, it is fancy yellow. Color becomes much harder to detect once a stone is set in a ring which also has some other colors.
Carat Weight Scale
Diamonds are sold by the carat (unit of weight). The value of carat into grams is 0.2 grams per carat. The carat weight ranges from 1-3. As the carat increases, the cost of the diamond also increases. Because a heavy diamond is rare to find and is too much valuable. The price of a diamond increases exponentially with the carat weight. Two diamonds having equal carat weight can also appear very different in size because of the difference in their shape.
So when you are buying a diamond you should focus on the cut grade, which is the most important factor in determining the overall appearance of a diamond. A diamond having a poor cut will seem dull even with excellent clarity and color., while a diamond having a proper cut with a slightly lower color or clarity will still look quite beautiful, due to its superior ability to create sparkle and brilliance.