Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
(
Rev. 4:3, R.V., "sardius;" Heb.
'odhem; LXX., Gr.
sardion, from a root meaning "red"), a gem of a blood-red colour. It was called "sardius" because obtained from Sardis in Lydia. It is enumerated among the precious stones in the high priest's breastplate (
Ex. 28:17, 39:10). It is our red carnelian.