only in (Revelation 21:19) The name is applied in modern mineralogy to one of the varieties of agate. It is generally translucent and exhibits a great variety of colors. So named because it was found near the ancient Chalcedon, near Constantinople.
·noun A cryptocrystalline, translucent variety of quartz, having usually a whitish color, and a lust...
Webster's Dictionary of the English Language
Mentioned only in Rev. 21:19, as one of the precious stones in the foundation of the New Jerusalem. ...
Easton's Bible Dictionary