When it comes to diamond grading laboratories, there is only one in the jewelry business that truly matters. That laboratory is the GIA (Gemological Institute of America) or more commonly known as GIA. GIA invented most of the systems in use today to grade the 4 C’s of diamonds (Cut, Color, Clarity, Carat), and they are completely unbiased in their grading process. This is why they are the most widely respected and only trusted source when one wants to know exactly the quality of a diamond.
Those in the diamond or jewelry business submit their product to GIA in order to obtain a certificate that outlines all of the important attributes pertaining to a particular diamond. This is done for a few reasons. One of the reasons is that diamonds are priced according to their quality. The difference in price between an F color diamond and a G color diamond or an SI1 clarity and an SI2 clarity can be a substantial amount. The other reason is that having the GIA certificate takes the person selling it out of the equation in the sense that it doesn’t matter what he or she says a particular diamond should be graded.
Unfortunately, there is a lot of inflated grading within the diamond business. This also pertains to certain diamond grading laboratories who can be anywhere from 1-5 grades off on attributes such as color and clarity. The reason they do this is because they feel the unsuspecting consumer will look at the shiny laminated certificate from ABC laboratory (example) and take the information as factual. It isn’t the consumer’s fault; it is something that needs to be corrected in the diamond business, and there are some very recent and concerted efforts to alleviate this problem.