Diamond Buying Guide
There are four variables that determine the value of a diamond. They are:
|• Carat Weight
Carat weight is the standard of measurement for the gemstone industry. One carat equals .2 grams. Historically, the carob bean was used as the standard. Although it was not precise, it had a fairly consistent weight. This is where the name "carat" came from.
Stones under one carat are generally broken down into points, where 100 points equals one carat (CT). 50 points equals 1/2 CT and 25 points is 1/4 CT. A .86 CT diamond is said to be 86 points, or an "86 pointer".
Note that carat weight does not really mean size. Because carats are weighed, the actual size of two diamonds having the same carat weight can vary, depending on the diameter, depth, length, and width. In other words, two diamonds having the same carat weight may appear to be different sizes if one is cut deeper or shallower than the other.
Clarity is an evaluation of internal characteristics, judged under 10x magnification. The Gemological Institute of America™ (GIA) has developed the grading system which is the international standard. The grades range from Flawless to Imperfect. One point to keep in mind is that stones with fewer or no inclusions are not necessarily better, but rather are rarer in nature, and therefore more expensive.
By the GIA definition, any diamond graded SI2 or higher has no eye visible inclusions. Inclusions rarely, if ever, affect the brilliance or fire of a diamond. Light enters a diamond from so many directions, that the microscopic inclusions do not interfere. Only major inclusions in an imperfect stone will reduce brilliance.
Color grading is also standardized using the GIA color grading system. Color in a diamond is more accurately described as lack of color. Most diamonds occur in nature having minute impurities causing them to have a slight yellowish cast. The more a diamond approaches absolutely colorless, the whiter it appears when cut. Colorless diamonds are quite rare in nature and are therefore the most expensive. The GIA color scale begins with the letter D and ends with Z, for white stones. Fancy colored diamonds such as yellow, pink, and blue are graded differently.