A diamond's grading report verifies that it is 100% natural, with no artificial treatments or enhancements, and independently confirms important gemological details.
The Gemological Institute of America (GIA) and American Gem Society (AGS) were both established by Robert Shipley in the 1930s.
Demand for diamonds created business for grading labs serving other world markets. The most respected of these are the Hoge Raad voor Diamant (HRD) and International Gemological Institute (IGI)*
Malls, chain stores and discount outlets have gained a reputation for using laboratories that inflate their diamonds' grades. If you're shopping in the USA and see a diamond grading report that was issued by a lab other than GIA or AGS you should do some research: Other legitimate labs do exist, but you want to avoid those with a reputation for overgrading.
The practice of "overgrading" hurts consumers and jewelers alike. For decades this was brazenly done by the European Gemological Laboratories (EGL International). This organization issued reports using GIA terms but with grading that was intentionally 2-4 grades higher. Unscrupulous sellers sold these overgraded diamonds until investigative news reports went viral and suppliers finally boycotted EGL International, putting them out of business.
There are still organizations willing to overgrade diamonds, or print reports with a grossly inflated "replacement valuation" which can be used to deceive shoppers. You can learn more on this topic and historic diamond value and pricing trends here.
We believe anyone selling you a diamond should not only use a reputable grading laboratory. They should also be willing to:
These guarantees indicate that your seller believes your diamond is absolutely worth what you're being asked to pay for it.