Diamond
Archimandrite Nikifor’s Biblical Encyclopedia
(Exod. 28:18; Ezek. 3:9) — the third precious stone in the second row of stones of the high priest’s breastplate of judgment, the hardest and most valuable of precious stones, found chiefly in the East Indies and Brazil. The diamond consists of pure carbon, and when subjected to the strong action of fire it burns away completely. A perfectly clear diamond is usually called a diamond of the first water. The diamond is mentioned among the precious stones of the king of Tyre (Ezek. 28:13). In Jeremiah (17:1) the engraving of Judah’s sin “with a point of diamond” expresses the depth and indelibility of that sin.