Opal Grading

First, depending on the type of opal, whether its Black, Boulder or White, will have a significant effect on its value. After that, in general terms, the larger the stone, the more valuable it is. But when natural or solid opals are graded, the most important features are the fire and colour. The term “play of colour” was created specifically to describe opal’s astonishing kaleidoscope of colours and hues. The most valuable have the strongest fire and the most vivid patterns in the stone.

A Red fire is the rarest and therefore the most valuable, then Orange, Yellow, Green, Indigo, Blue and Violet, all of which are still breath-takingly beautiful, but more readily available. Other factors may influence value, like shape for white and black opal and the presence of nature’s hallmarks.