Onyx
A hail; claw; hoof, (Heb. shoham), a precious stone adorning the breast-plate of the high priest and the shoulders of the ephod (Ex. 28:9-12, 20; 35:27; Job 28:16; Ezek. 28:13). It was found in the land of Havilah (Gen. 2:12). The LXX. translates the Hebrew word by smaragdos, an emerald. Some think that the sardonyx is meant. But the onyx differs from the sardonyx in this, that while the latter has two layers (black and white) the former has three (black, white, and red).
Passages cited in this entry
M. G. Easton, Illustrated Bible Dictionary, 3rd edition (1897). Public domain; text from the Christian Classics Ethereal Library. A nineteenth-century Protestant reference: its dates, archaeology and judgements reflect the scholarship of its time and are not Imago Dei's editorial position.