Ruby
Archimandrite Nikifor’s Biblical Encyclopedia
(red) (Ex. 28:17)—a precious stone of red or fiery color, valued by the source just below diamond. It reports renowned rubies from India and from Sardis in Lydia, from which the terms sard or sardius were connected (Rev. 4:3), and cites Pliny’s high estimate of Babylonian rubies. The ruby occupied the first position in the first row of stones on the high priest’s breastpiece of judgment.