How to Read a Diamond Certificate in Five Minutes

A grading report has more useful information on it than the 4Cs headline figures — fluorescence, polish, symmetry and proportions all affect how a stone actually looks and performs.

Fluorescence in particular is frequently misunderstood: faint to medium blue fluorescence is usually invisible face-up and can make a warmer-colored stone appear whiter, sometimes at a lower price than an equivalent non-fluorescent stone.

We walk through a real GIA report line by line so you know what you're actually paying for.

Editorial disclosure: this guide reflects our independent research and is not sponsored by any retailer named in it.