Gemstone encyclopedia
Onyx — meaning, history and vintage jewelry
Onyx is a banded chalcedony; in the jewelry trade the name is used for the solid black material, while black and white banded stone is used for cameos. Almost all black onyx has been dyed, a practice that goes back to antiquity and is accepted for the species. At 6.5 to 7 on the Mohs scale it cuts into the crisp plaques and rods that define Art Deco design.
What onyx is
Onyx does two jobs in period jewelry. In Victorian mourning pieces it supplies a deep matte black that reads as restraint. In Art Deco it supplies graphic contrast: a black frame around a diamond, a black rod against coral, a black ground for a carved plaque.
Because the material is dyed, harsh chemicals and heat can affect it, and chips reveal the paler stone underneath.
Color and hardness
- Species
- Chalcedony, a microcrystalline quartz
- Color
- Solid black, or black banded with white
- Mohs hardness
- 6.5 to 7
- What that means in wear
- Tough and even textured, but the polish scratches and dulls if it is treated carelessly.
How to care for onyx
- Wipe with a soft damp cloth and dry immediately.
- Avoid ultrasonic and steam cleaning, which can affect dyed material and loosen glued plaques.
- Keep away from perfume, solvents and household cleaners.
Our full house rules, including what the one year warranty does and does not cover, are in the care & warranty guide.
History and symbolism
Used for Roman cameos and intaglios, then central to Victorian mourning jewelry, then reinvented as the graphic backbone of 1920s and 1930s design.
In the nineteenth century it was the color of formal mourning. Later it lost that meaning entirely and became simply modern and architectural.
Onyx in vintage and antique jewelry
Victorian mourning brooches and lockets; Edwardian black and white enamel and onyx combinations; Art Deco panel bracelets, dress rings and cufflinks pairing onyx with diamonds, coral or jade.
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Onyx 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
- Is black onyx dyed?
- Nearly always. Dyeing chalcedony black is an ancient practice and is standard for the material, but it is why aggressive cleaning should be avoided.
- Why does onyx appear so often in Art Deco jewelry?
- It cuts into precise geometric shapes and gives designers a true, flat black to draw with against diamonds and platinum.
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