Color Grading System - GIA Gemologists

Sapphire Ring Co have incorporated the official GIA Sapphire and Ruby color map below. The charts explain the color grading system used by all GIA G.G. gemologists in their color grading of Sapphires & Rubies. The charts illustrate the wide variations in color gradings for Sapphire and Rubies as well as the three main factors which make up a Sapphire's color: Hue, Tone & Saturation.

Please feel free to contact us at any time with any questions you may have on Sapphire color grading and how this is used today to give each Sapphire it's final color grade. Understanding these distinctions is important in properly choosing your perfect color in a natural Sapphire or Ruby.



GIA Color Grading Scale

Hue Table

The GIA Colored Stone Grading System includes a description system that uses 31 hue names to describe colored gemstones.


Name Code Color
very slightly greenish blue vslgB
Blue B
violetish blue vB
bluish violet bV
Violet V
violetish purple* vP*
Purple P
reddish purple rP
red-purple or purple-red RP/PR
strongly purplish red stpR
slightly purplish red slpR
Red R
orangy red oR
red-orange or orange-red RO/OR
reddish orange rO
Orange O
yellowish orange yO
orangy yellow oY
Yellow Y
greenish yellow gY
yellow-green or green-yellow YG/GY
strongly yellowish green styG
yellowish green yG
slightly yellowish green slyG
Green G
very slightly bluish green vslbG
bluish green bG
very strongly bluish vstbG
green-blue or blue-green GB/BG
very strongly greenish blue vstgB



The GIA Tone Scale helps you judge a gem's brightness or darkness. Three key standards to remember are (3) Light, (5) Medium. and (7) Dark.


Name Scale Tone
very light 2
Light 3
medium light 4
Medium 5
medium dark 6
Dark 7
very dark 8


Saturation Scale

Use the GIA saturation scale to judge a gem's strength of color. In warm colors, weaker saturations of 1, 2, or 3 appear brownish. In cool colors the same values look grayish. In both warm and cool colors, gems with saturations of 4, 5, or 6 are almost always more valuable if all other factors are equal.


Name Cool Color Scale Warm Color Name
slightly grayish
slightly brownish
very slightly grayish
very slightly brownish
moderately strong
moderately strong
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