Gemstone encyclopedia
Opal — meaning, history and vintage jewelry
Opal is hydrated silica made of microscopic silica spheres that diffract light into the spectral flashes called play of color. It is soft, at 5.5 to 6.5 on the Mohs scale, and contains up to a tenth of its weight in water. Opal must never be cleaned ultrasonically or with steam, and it should not be stored anywhere hot or bone dry. Handled properly, Victorian and Art Nouveau opals survive beautifully.
What opal is
Body color matters as much as the play of color. Black opal from Lightning Ridge shows the brightest fire against a dark ground; white and milky opal is softer; Mexican fire opal is orange and often faceted, sometimes with no play of color at all.
Doublets and triplets, where a thin slice of opal is backed or capped, exist in antique and mid century jewelry. They are legitimate but must be disclosed, and they are far more vulnerable to water and solvents than a solid stone.
Color and hardness
- Species
- Hydrated silica, non-crystalline
- Color
- White, gray, black or orange body color with spectral play of color
- Mohs hardness
- 5.5 to 6.5
- What that means in wear
- Soft, and it contains water. Opal needs a protective setting and gentle handling for life.
How to care for opal
This is one of our delicate stones. Pearls, opal, emerald, turquoise, coral, moonstone and tanzanite must never go near an ultrasonic or steam cleaner, and they should be kept away from perfume, cosmetics and household chemicals.
- Never use ultrasonic or steam cleaning. This is not a preference, it is how opals crack.
- Clean with a barely damp soft cloth and dry gently.
- Avoid extreme dryness, direct heat and sudden temperature change; keep away from perfume and cosmetics.
- Store away from harder stones so nothing scratches the dome.
Our full house rules, including what the one year warranty does and does not cover, are in the care & warranty guide.
History and symbolism
Roman writers prized opal highly. Australian discoveries from the 1880s transformed supply just as Art Nouveau designers were looking for exactly its dreamlike quality, and Queen Victoria's fondness for opal did much to counter the superstition that it was unlucky.
Hope and imagination. The idea that opal brings bad luck is a nineteenth century literary invention, not a historical belief.
Opal in vintage and antique jewelry
Victorian opal and diamond clusters; Art Nouveau plique a jour and gold work using opal for its shifting light; Edwardian platinum pieces; Arts and Crafts silver with cabochon opals.
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Opal pieces in our collection
Every curated vintage, antique and estate piece is one of a kind and checked by our jewelry specialists in the Netherlands. If nothing is right today, we will look for it.
Frequently asked questions
- Can I wear an antique opal ring every day?
- Only with care. Opal is soft and sensitive to knocks and to sudden temperature change. A bezel or a well protected setting helps, but a daily ring is a real risk for a fine antique opal.
- Is it true that opals crack?
- Opal can craze if it is dried out, heated or shocked. Normal wear and sensible storage prevent it. Ultrasonic cleaning is the most common cause of avoidable damage.
- What is an opal doublet?
- A thin layer of opal bonded to a dark backing to strengthen it and deepen the color. It is legitimate when disclosed and needs even more protection from water and solvents than a solid opal.
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