Diamond District NYC has the largest selections of Diamonds in New York City
There are five diamond labs that frequently grade and certify diamonds. They are (in order of reputation: highest to lowest): Gemological Institute of America (GIA), American Gem Society (AGS), Hoge Raad voor Diamant (HRD), International Gemological Institute (IGI), and European Gemological Laboratory (EGL).
Diamond labs form a useful part of the overall diamond buying process, particularly for non-diamond experts. They give the novice buyer confidence that the gem they are buying is there or thereabout the right grade; however, it might interest you to know that there is no single authoritative body that dictates what “G color” is the official G color, or what “VS1 clarity” is the official VS1 clarity, etc. This means some labs over grade in some areas and under grade in others relative to their peers (i.e. the other diamond labs listed above).
It’s All About Consistency and Relativity Not How Strict The Lab Is
A NYC diamond district wholesaler will often send thousands of diamonds at a time to a lab for grading. It is considered statistically excellent if that lab grades 95% of them the same consistency. The challenge is that the other 5% are off. Sometimes higher than the average some times lower. You don’t want to be the one who buys the lower . . . but we digress.
The real message here is that it’s about relativity. You as a consumer should not care for example if you are buying an EGL diamond that is of VS1 clarity if it is the same clarity as a GIA diamond of VS2 clarity (all else being equal) as long as you pay the GIA VS2 price (or better).
It is broadly accepted in the diamond industry that GIA is the most consistent and tightest grader in the market. Their diamonds should command a premium over other labs. The “game” of the less scrupulous jeweler is to take an unknowing customer who is looking for a VS1 diamond, who knows the GIA price but does not know the difference in labs, and then sell them a VS1 diamond from a looser lab for the same price, where the diamond should have been sold for a lot less. The moral here then is that if you’re unsure of the relativities, stick with GIA graded diamonds.