A dark semiprecious stone that is used in cameos and rings is an example of onyx.
Origin of onyx
- Middle English onix from Old French from Latin onyx from Greek onux nail, onyx nogh- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- Before 1300 as onix, in about 1250 as oneche, from Old French oniche or onix, or from Latin onyx, from Greek ὄνυξ (onyx).