Where does “ónix” come from?

ónix (Spanish) comes from Latin onyx, from Ancient Greek ὄνυξ, from Proto-Indo-European h₃nogʰ- — claw, nail; nail.

ónix (Spanish): onyx

Definitions

Step	Language	Word	Meaning
1	Latin	onyx	onyx, yellow marble; A yellowish precious stone;...
2	Ancient Greek	ὄνυξ	claw, nail, hoof, talon; Anything which resembles...
3	Proto-Indo-European	h₃nogʰ-	claw, nail; nail

ónix — Etymology, Origin & Word History | Etymology Explorer