Colored Stone Color Grading Terms
The following is a list of hue, tone and saturation scales with terms and their abbreviations for describing gem color.
Guidelines for color ranges of each quality, from Excellent to Fair, are listed above the color stone price charts. The hue is abbreviated in the left column and the tone and saturation ranges are abbreviated as numbers (tone/saturation).
For example, vslbG 5/4 (very slightly bluish Green Hue, Medium Tone, Moderately Strong Saturation) is a Very Good quality color for Emeralds.
| HUE | ABBREVIATION |
|---|---|
| Purple | P |
| reddish Purple | rP |
| Red-Purple or Purple-Red | RP/PR |
| strongly purplish Red | stpR |
| 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 |
| strongly yellowish Green | styG |
| yellowish Green | yG |
| slightly yellowish Green | slyG |
| Green | G |
| very slightly bluish Green | vslbG |
| bluish Green | bG |
| very strongly bluish Green | vstbG |
| Green-Blue or Blue- Green | GB/BG |
| very strongly greenish Blue | vstgB |
| greenish Blue | gB |
| very slightly greenish Blue | vstgB |
| Blue | B |
| violetish Blue | vB |
| bluish Violet | bV |
| Violet | V |
| violetish Purple | vP |
