A nail, the eleventh stone in the high priest's breastplate, Exodus 28:20 . The modern onyx has some resemblance to the agate; and the color of the body of the stone is like that of the human nail; hence its name. The Hebrew word so translated is not known with certainty to signify the onyx; but denoted some valuable stone, Genesis 2:12; Exodus 25:7; 28:9-12,20 . A species of marble resembling the onyx was known to the Greeks, and may have been the "onyx-stones" stored up by David for the temple, 1 Chronicles 29:2 .