Natural Opal Gemstones

Natural Opal Gemstones

Opal is hydrated silica (SiO2·nH2O), and unlike most gemstones it has no crystal structure. Its color ranges from milky white and pale blue in common opal to the vivid orange and red of fire opal, and black opal has the darkest, most dramatic background. What sets precious opal apart is its play-of-color: flashes of rainbow hues that move across the stone as it turns. With a Mohs hardness of 5.5 to 6.5, opal is soft and needs care.

Read more ↓

13 products

Gemstone guide

Natural Opal Gemstones

About opal

Opal is the birthstone for October. Its play-of-color comes from tiny spheres of silica stacked in a regular pattern, which split white light into spectral colors, much like a prism. Australia was long the main source and is famous for black opal from Lightning Ridge, while Ethiopia has produced large quantities of bright opal since the late 2000s, and Mexico is known for transparent orange fire opal.

What you'll find in this collection

Most of our opal comes from Ethiopia, with a few stones from Australia, Mexico, Indonesia and elsewhere in Africa, and all are untreated. You'll find mainly oval and pear cabochons from under a carat to over 26 carats, in white, crystal and darker body colors, plus the occasional faceted stone, rough piece or bead.

How to recognise opal

Play-of-color is the defining feature: patches of spectral color that shift with the viewing angle, in patterns collectors describe as pinfire, flash or harlequin. Ethiopian opal is often hydrophane, meaning it can absorb water and turn temporarily transparent before returning to its normal look as it dries. Imitations usually show a regular, snakeskin-like pattern in the color patches under a loupe.

Caring for opal

Opal contains water and is sensitive to heat, sudden temperature changes and knocks. Clean it with a soft damp cloth, never in ultrasonic or steam cleaners, and keep Ethiopian hydrophane opal away from oils, lotions and long soaking, which it can absorb. Store opal apart from harder gems.

Every stone is natural, and each listing gives its weight, size, origin and treatment, with photos of the actual stone.