diamond

Concise Bible Dictionary:

Corundum (Var. Sapphire)
Diamond

Strong’s Dictionary of Hebrew Words:

Transliteration:
yahalom
Phonic:
yah-hal-ome’
Meaning:
from 1986 (in the sense of hardness); a precious stone, probably onyx
KJV Usage:
diamond

Jackson’s Dictionary of Scripture Proper Names:

he will smite down