2 occurrences in 2 dictionaries

Reference: Sardine, Sardius

Morish

odem, ???????. One of the precious stones in the breastplate. Ex 28:17; 39:10. It also embellished one of the foundations of the holy Jerusalem. Re 21:20. It was one of the stones that covered the king of Tyrus (doubtless portraying Satan before his fall). Eze 28:13. In heaven One who sat upon the throne was "to look upon like a jasper and a sardine stone." Re 4:3. It is supposed to be the sard, a superior variety of agate, of various colours, some blood-red, and others of a golden hue.

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Smith

(red) (Heb. odem) the stone which occupied the first place in the first row of the high priest's breastplate.

Ex 28:27

The sard, which is probably the stone denoted by odem, is a superior variety of agate, sometimes called camelian, and has long been a favorite stone for the engraver's art. Sardis differ in color: there is a bright-red variety, and perhaps the Hebrew odem from a root means "to be red," points to this kind.