Opal body tone and brightness scale

Sick of trying to guess what the body tone and brightness of your opal is? Now you can accurately measure from a calibrated scale.

This scale has been created with a durable plastic material and is compact to ensure you can take it anywhere. It will help you grade your opal with ease - only to be used as a guide. The body tone(N) values have been measured by Anthony Smallwood – the author of the official grading system used worldwide. The brightness is simplified into 5 levels to support the measure of an opals brightness(B). It also has a millimeter measurement down the side to measure your opal when grading them.

Instructions are on the scale. Opals not included.