Sardonyx

A precious stone associated with one of the foundations of the holy Jerusalem (Rev. 21:2020The fifth, sardonyx; the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst. (Revelation 21:20)). The word does not occur in the AV of the Old Testament. Aquila, in his Greek version, uses it for the onyx in Genesis 2:1212And the gold of that land is good: there is bdellium and the onyx stone. (Genesis 2:12). It is judged to be a variety of chalcedony, or of agate, of various colors, with stripes of a different shade.