No two of these stones show the same colours twice - that is the whole magic. A natural opal bracelet from the 1970s.
Opal is the only gemstone on earth with play of colour: flashes of green, blue, orange and red that move as the stone moves, caused by microscopic silica spheres splitting light like millions of tiny prisms. No two opals are alike, no photograph does one justice, and no stone in the antique world is more misunderstood - both its famous "bad luck" myth and its reputation for fragility are wildly overstated, and both have kept prices kinder than the stone deserves.
The kinds of opal you will meet
| Type | What it is |
|---|---|
| White opal | Light body with colour play - the classic of Victorian and mid-century jewelry, and the most common in antique pieces |
| Black opal | Dark body that makes the colours burn - the rarest and most valuable, mostly from Lightning Ridge, Australia |
| Crystal opal | Translucent body you can see into, with colour floating in the depth |
| Fire opal | Orange to red body colour, often faceted, mostly Mexican - prized for the body colour itself |
| Boulder opal | Opal still attached to its ironstone host rock, cut as one piece |
| Doublets and triplets | A thin opal slice glued to a dark backing (and under a clear dome, for triplets). Honest constructions, but priced far below solid stones - and they must never be soaked |
Opals in the old eras
The Victorians adored opals - Queen Victoria gave them as wedding gifts and wore them constantly, which did more to bury the bad-luck superstition than any argument could. The stone suited the era's romanticism perfectly: mysterious, individual, alive. Art Nouveau made opal one of its signature stones, loving exactly what the diamond trade could not price - effect over carat. And the Australian finds of the late 1800s brought opal into everyday jewelry, which is why so many lovely white opals turn up in rings from 1900 to 1970.
The twenties knew how to frame a stone that changes its mind in every light: an Art Deco opal and diamond ring in 18K white gold.
The honest truth about opal care
Opal contains a few percent water and is softer than most gems - around 5.5 to 6.5 on the Mohs scale, similar to glass. That calls for sense, not fear:
Do wear your opal often (it is not harmed by normal life on a hand), wipe it with a soft damp cloth, store it away from harder jewelry that could scratch it, and have settings checked now and then.
Don't put an opal in an ultrasonic cleaner, subject it to sudden temperature shocks, park it for years in bone-dry heat, wear it for gardening and gym sessions, or soak a doublet or triplet in water - moisture can creep into the glue line and cloud it.
That is the whole regime. A solid opal that survived a century of Victorian daily life is not the diva it is rumoured to be.
Buying an antique opal well
Judge the play of colour first: the more of the surface that lights up, and the more red and orange in the mix, the better the stone (red flash is rarer than green and blue). Check the stone under a loupe for cracks - called crazing - because a crazed opal should be priced accordingly. Confirm whether it is solid or a doublet by looking at the side: a doublet shows a straight, sudden line where opal meets backing. And then choose with your eyes, because opals are the least standardized gem there is, and the right one announces itself.
Frequently asked questions
What makes opals change colour?
Play of colour: microscopic silica spheres inside the stone diffract light into shifting flashes. Opal is the only gemstone that does this.
Are opals really unlucky?
No - the superstition largely traces to a 19th century novel, and Queen Victoria spent a reign disproving it. The myth's only real effect is keeping opal prices friendlier than the stone deserves.
Are opals too fragile to wear?
They need sense rather than fear: no ultrasonic cleaners, no temperature shocks, no gym. Solid opals in antique rings have survived a century of hands already.
What is the difference between a solid opal and a doublet?
A doublet is a thin slice of real opal glued to a dark backing to strengthen the colour. Viewed from the side, you can see the straight glue line. Doublets are honest but worth much less than solid stones, and must not be soaked.
Which opal colours are most valuable?
Broad, bright play of colour with red and orange flashes ranks highest, and dark-bodied stones show it best - which is why black opal is the most valuable type.
How should I clean an antique opal?
A soft cloth, barely damp, nothing more. Never an ultrasonic cleaner, and never a long soak - especially not for doublets and triplets.
Read next: Are opals bad luck? · What is moonstone? · How to clean antique jewelry
Line Evelin
