Opal Brightness and Body Tone Guide

Opal Galaxy does not support the opal body tone and brightness grading systems. We will not provide an opinion on any of our opals on body tone or brightess scales from hereon.

We have come to this decision after over a decade in the industry trying to support the Opal Body Tone and Brightness grading systems. In our honest opinion, these grading charts were invented by people trying to complicate things in the industry. These complications take away from the nature of opals in that they are all unique to each other. We never really agreed with these charts and will no longer be supplying our opinions of body tones and brightness. An important thing to note is that these charts are not recognized by any official gemologist association or certification company (for example GIA, GRS ect). We believe that grading opals works against what opals are really all about; in that each one is unique to the other. We do not believe they should be so easily categorized like other colored gemstones that all look the same as each other.

Another important thing to note is that grades are subjective and may differ from person to person. Because of this, they are rarely accurate as everyone has a unique opinion on how the opals should be graded. The brightness chart is also very confusing to buyers when some sellers use a chart of 1 being the brightest and 5 being the least brightest, and others use a chart of 5 being the brightest and 1 being the least brightest. We ask that people judge our opals for themselves without a grading.

All of the photos and videos that we provide are very true to how the opals look in person with light exposure.

Opal Body Tones

There are 4 main types of Australian Opal that people are concerned with body tone. These are Black Opal, Dark Opal or Semi Black Opal, White Opal and Crystal Opal. The shade of body tone on these can usually be determined by looking at the back sides potch color (or transparency in crystals). With black and dark opals, the shades can sometimes vary from jet black to a lighter shade of black and grey as the potch isn’t always of the same shade/tone in each opal.

potch of a black opal
An example of a black opal with different shades of potch

Crystal opals are transparent and usually don’t have any or much potch on the back of them. If there is some potch and the opal is still transparent then they are still considered a crystal opal. If the shade of the transparency is a lot darker with deeper colors in the opal then this is a good indication that the opal is either a black crystal or dark crystal opal.

Gem Blue Crystal Opal 2.75 ct

Light will pass through a crystal opal

 An example of a black crystal opal

White opals have white potch as opposed to black or dark potch in them.

Boulder opal, and sandstone crystal boulder opal are not usually judged for their body tone as they are always so different and unique. The ironstone usually gives good strong colors in the opal’s face. An exception to this is black boulder opal which is much darker ironstone host rock with higher manganese levels.

For a person to know a grading level of body tone in an opal should not be a determining factor in purchasing. This is because there are low and high grades of opals which also influence how an opal looks and is valued. With body tones; we will always classify the type of opal (eg Black Opal, Dark Opal, Crystal Opal ect) however we will not provide a grading based on the opal body tone chart.

Opal Brightness

If an opal is well polished (like all of the opals that we sell) then they are the brightest that they can possibly be. The brightness of an opal comes from several determining factors. Them being exposure to light, play of color, specific colors in the opal, pattern and the amount of potch (colorless opal) in the opal.

We ask that people judge our opals by how they look in our photos and videos; these are all very true to how the opal looks in real life with light exposure.

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