Onycha

Meaning: a nail; claw; hoof

Hebrew: sheheleth; Ex. 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.