Crystal Opals

The definition for a crystal opal continues to confuse many professionals, but a stone is generally considered to be a crystal opal if it has any kind of transparent or translucent quality. It is possible for a black opal, white opal or semi-black opal to also be a crystal opal.

 Appearance

The translucent or transparent property of a crystal opal is referred to as the 'diaphaneity' of the stone. If you are holding a stone, and find that it is possible for light to pass through it, or that you can see through the stone entirely, there is a high likelihood that you are holding a crystal opal. Like other opals, crystal opals can also offer a magnificent 'play of colour'.

It must be said though that a boulder opal can never be a crystal opal. Despite the fact that some boulder opals may have translucent features, the presence of an ironstone layer on the back means that they will never be categorized as crystal opals.

The translucent feature that a crystal opal integrates often provides a greater degree of clarity and vibrancy than its more opaque counterparts. A crystal opal that is white or pale white in body tone is generally considered more valuable that a stone that is completely white and opaque. A black crystal opal may have a better vibrancy than a black, opaque stone making it more valuable.

While crystal opals are generally cut in a standardized oval form, it is not uncommon for them to be cut in freeform or teardrop form, in an attempt to maximize the size of the stone, as well as its carat weight. Crystal opals are cut with high cabochon in order to improve the vibrancy of the colours they display.

Value

A crystal opal of the highest quality may fetch a price that amounts up to AUD $2500 per carat. A crystal opal will always be more valuable than a stone with a similar body tone, without the clarity rendered by translucence. The more the diaphaneity of an opal stone, the greater its value.

Origin

The crystal opal is generally mined in South Australia, as well as New South Wales. These stones are commonly found in the same locations as black or white opals. One of the most popular mining grounds for crystal opals was White Cliffs in New South Wales.