Learn · Gemstones and pearls
The 7 pearl value factors
GIA describes every pearl by seven factors: size, shape, colour, luster, surface, nacre and matching. Change each one on the pearl below and watch the report-style description build up. GIA classifies pearls; it does not grade them into a single score, and this page puts no price on any of them.
Change each of the seven factors on the pearl and watch the description build up.
Hue, tone and saturation
How the trade describes a coloured stone's colour: hue, tone and saturation
Birthstones around the world
Every month on the American, British, Japanese and nine-gem lists
Where gems come from
A world map of where each gem is mined, today and historically
Gem treatments explained
Usual treatments gem by gem, the trade codes, care and disclosure rules
Cutting angles and light
Change a stone's cutting angles and follow the light: where it returns and where it leaks Preview