(1.) A precious gem (Hebrews yahalom', in allusion to its hardness), otherwise unknown, the sixth, i.e., the third in the second row, in the breastplate of the high priest, with the name of Naphtali engraven on it (Exodus 28:18; 39:11; R.V. marg., "sardonyx.")
(2.) A precious stone (Hebrews shamir', a sharp point) mentioned in Jeremiah 17:1. From its hardness it was used for cutting and perforating other minerals. It is rendered "adamant" (q.v.) in Ezek. 3:9, Zechariah 7:12. It is the hardest and most valuable of precious stones.