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Related to sardonyx: Chrysoprasus, birthstones
An onyx with alternating brown and white bands of sard and other minerals.
(Minerals) a variety of chalcedony with alternating reddish-brown and white parallel bands, used as a gemstone. Formula: SiO2
[C14: via Latin from Greek sardonux, perhaps from sardion sardine2 + onux nail]
sar•don•yx(sɑrˈdɒn ɪks, ˈsɑr dn-)
an onyx composed of layers of sard and chalcedony of another color, usu. white: used as a gem and to make cameos.