Body tone scale

The Body Tone Scale measures the lightness or darkness of an opal’s background, ranging from white to black. To use it, place your opal face-up on the chart and slide it along until its tone matches one of the reference samples, helping you accurately determine its body tone grade.

Black
Dark
Light
Brightness scale

The Brightness Scale measures the intensity and vibrancy of an opal’s play of colour, indicating how strongly the colours appear under light. To use the scale, place your opal face-up on the chart and move it along until its brightness most closely matches one of the reference levels. This helps you accurately assess the opal’s overall brilliance and visual impact.

B5_Vivid
B5
Vivid
B4_Very Bright
B4
Very Bright
B3_Bright
B3
Bright
B2_Moderately Bright
B2
Moderately Bright
B1_Subdued
B1
Subdued
Download Printable Body Tone & Brightness Guide
Please note:

This Body Tone and Brightness Scale is intended as a general reference only. Any decisions made using this guide are at the user's discretion and no liability is assumed. For most accurate results, laser print this guide on Artboard 350gsm paper stock or similar, with print quality set to high.