Hastings' Dictionary of the Bible (1898)
DI'AMOND. Ex 28:18; Eze 28:13. " — Canon Cook. The claims of jasper, onyx, chalcedony, emerald, and rock-crystal to be the diamond of the Bible have all been urged. Its diversity from any other stone in the high priest's breast-plate will incline some minds to advocate rock-crystal. For Jer 17:1, see Adamant.