The Encyclopedia · Stones & materials
Onyx
A black stone, usually dyed chalcedony, used for strong graphic contrast with diamonds and gold.
Black onyx in jewelry is almost always chalcedony, a form of quartz, dyed black, a practice that goes back to antiquity. Its deep, even black made it essential to Art Deco jewelers, who paired it with diamonds and platinum, and to the gold jewelry of the 1970s, from Van Cleef & Arpels to Cartier.
What to look for
Onyx should be evenly black and well polished. Chips at edges are the most common damage.
In the collection
Onyx, available now
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