What is "onycha"

Onycha \On"y*cha\, n. [NL., from L. onyx, -ychis, onyx, also, a kind of mussel, Gr. ?, ?. See 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.]

n. 1 (context obsolete English) An ingredient of the Mosaic incense, probably the operculum of some kind of strombus. 2 (context obsolete English) The precious stone onyx.

Onycha (Greek: ονυξ), along with equal parts of stacte, galbanum, and frankincense, was one of the components of the consecrated Ketoret (incense) which appears in the Torah book of Exodus (Ex.30:34-36) and was used in the Jerusalem's Solomon's Temple. This formula was to be incorporated as an incense, and was not to be duplicated for non-sacred use. What the onycha of antiquity actually was cannot be determined with certainty. The original Hebrew word used for this component of the ketoret was שחלת, shecheleth, which means "to roar; as a lion (from his characteristic roar)" or “peeling off by concussion of sound." Shecheleth is related to the Syriac shehelta which is translated as “a tear, distillation, or exudation.” In Aramaic, the root SHCHL signifies “retrieve.” When the Torah was translated into Greek (the Septuagint version) the Greek word “onycha” ονυξ, which means "fingernail" or "claw," was substituted for shecheleth.