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Sardius
Sardius [nave]
SARDIUS, a precious stone. In the breastplate, Ex. 28:17; 39:10.In the garden of Eden, Ezek. 28:13.
Seen in John's apocalyptic vision of the foundation of the New Jerusalem, Rev. 21:20.
Figurative
Rev. 4:3.
Also see definition of "Sardius" in Word Study