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Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
  • Opal Body Tone and Brightness Scale
Opal Body Tone and Brightness Scale

Opal Body Tone and Brightness Scale

$12.00 USD
Description

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 designed by Black Opal Direct 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 for use are on the scale. Opals not included.
Shipping

Shipping methods:

  • Within Australia: Express Post
  • International: Standard and expedited shipping options available

Frequently asked questions
What is the opal body tone and brightness scale?

The opal body tone scale is a classification system used to describe the base color of an opal, ranging from black (N1) through dark to light (N9). It helps determine the type of opal and contributes to its overall value. The brightness scale measures how vivid and intense the play-of-color is in an opal. It ranges from B1 (faint brightness) to B7 (exceptionally brilliant). Higher brightness usually indicates higher value.

Learn more about these scales here.
Who uses the body tone and brightness scale?

These scales are widely used by gem cutters, traders, appraisers, and collectors to classify opals consistently. They’re recognized internationally as an essential part of opal grading.
Does the scale work for doublet and triplet opals?

No. Body tone and brightness scales are intended for solid opals only. Doublets and triplets are treated differently, as their body tone is influenced by their backing.

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