GIA Certified Diamonds

The Gemological Institute of America invented the grading vocabulary the entire trade now uses — the colour letters, the clarity scale, the four Cs themselves. It is a non-profit, it does not buy or sell stones, and it is generally accepted as the strictest of the major laboratories.

Strict has a practical meaning. The same physical diamond submitted to different laboratories can come back with different letters, and the gap is not random: it usually runs in the direction of the more generous grader. A stone graded H by GIA may well be called G elsewhere. This is why comparing two certificates from two laboratories on price alone is misleading, and why a GIA stone that looks more expensive per carat is often not more expensive at all once the grades are aligned.

GIA grades both mined and laboratory-grown diamonds, and reports the growth method on the latter. Every stone in this collection carries its own report, and the report number is on the product page so you can verify it directly with GIA before you buy anything.

Each one also has a 360° video, because a certificate describes a stone but it does not show you one.