Category:Onycha

On"y*cha, n. Etym: [nl., from l. onyx, -ychis, onyx, also, a kind of Mussel, gr. Onyx.]

1. An ingredient of the mosaic incense, probably the operculum of Some kind of strombus. Ex. xxx. 34.

2. The precious stone called onyx. [r.]

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---excerpt from the Illustrated Bible Dictionary

Onycha - A nail; claw; hoof, (Heb. sheheleth ; Exodus 30:34), a Latin word applied to the operculum, i.e., the claw or nail of the strombus or wing-shell, a univalve common in the Red Sea. The opercula of these shell-fish when burned emit a strong odour "like castoreum." This was an ingredient in the sacred incense.