Crystal Opal

Crystal Opal is precious opal with a transparent to translucent body, regardless of body tone. The term refers to the clarity of the background, not a crystal structure, since opal is actually amorphous.

Because light passes through the stone, the play-of-color seems to float with remarkable depth and three-dimensionality. Crystal opal can have a light, dark, or 'black crystal' body tone; the darker and more transparent it is, the more valuable it tends to be.

It is found in Australian fields such as Lightning Ridge and Coober Pedy, as well as in Ethiopia, and is prized by collectors for its luminous, glassy fire.

Crystal opal forms like other precious opal: silica-rich water deposits microscopic, uniformly sized silica spheres in voids and seams, and the ordered stacking of these spheres diffracts light into color.

What sets crystal opal apart is its low impurity content and high transparency, allowing light to travel through the stone and illuminate the color from within. Cleaner, more transparent silica gel produces the clearest material.

Sources include the New South Wales (Lightning Ridge) and South Australian opal fields, and the volcanic deposits of Wollo, Ethiopia, which often yield transparent crystal opal.

Identify crystal opal by transparency or translucency: you can see into or through the stone, and the play-of-color appears suspended at depth rather than sitting on the surface.

Opal is amorphous, hardness 5.5-6.5, with vitreous-to-waxy luster and conchoidal fracture. Crystal opal's clarity distinguishes it from milky white opal and opaque common opal.

Beware of glass imitations and resin that mimic transparency but lack true directional play-of-color, and of doublets/triplets that place a clear cap over thin opal. In genuine crystal opal the color and clarity continue throughout the solid stone.

Crystal Opal is a sought-after gemstone for rings, pendants, and earrings, valued for its glowing, deep play-of-color. Transparent stones with strong color can be very valuable, especially dark 'black crystal' opal.

Its clarity also allows some pieces to be faceted, though most are cut as cabochons to display color. It is popular with collectors and high-end jewelry designers.

Metaphysically opal is linked to inspiration, clarity, and emotion. These associations are cultural beliefs and not scientifically demonstrated.