Diamond colour, D to Z
GIA's colour scale runs from D, colourless, to Z, light yellow or brown. Move one diamond along it and see it two ways: face-up, as it is worn, and face-down on a white tray, as a grader sees it.
Face-down, the white tray and the long path of light through the stone make the body colour easier to see. Face-up, the sparkle makes body colour harder to judge. GIA grades table-down against masterstones.
The whole scale
GIA's 23 grades in its five groups, face-down. Tap a grade to view it above.
Two grades side by side
Face-up
Face-down on the tray
How colour is graded
Table down, controlled light
At the GIA Laboratory the diamond is placed table down under highly controlled lighting and compared with a set of master comparison diamonds of known grade.Not a matter of opinion
GIA's point: colour is judged by trained graders against masterstones, not by eye in a showroom. Colour differences between neighbouring grades are very subtle, yet they change quality and price.Yellow, brown or grey
The normal range runs from colourless to light yellow, light brown or light grey. Beyond Z the colour is strong enough to be graded as a fancy coloured diamond on a different system.This page is a drawing
Screens cannot show a grade: their colour, brightness and the size of the image all change what you see. The renders show the direction of the scale, not a reference to grade against.Sources
GIA 4Cs, A guide to diamond color, D to Z: table down under controlled lighting against master comparison diamonds; the five groups and their descriptions quoted on this page. GIA, Diamond quality factors: masterstones; normal range colourless to light yellow and brown. GIA 4Cs, Diamond color: "color isn't a matter of opinion"; controlled lighting and masterstones.
Images: ray-traced round brilliants (JewelLoop renderer, diamond refractive index and dispersion) with a yellow body colour that increases along the scale. GIA does not publish colour coordinates for its grades; the strength of colour here is illustrative.