Assertion: chalcedony's color | /r/HasProperty | characteristic
Facets:
Source sentences:
text: Sardonyx, as recorded by Plinny (xxxvii.75 -- as translated by King, 1865) provides an early example of gemstone forgery: It seems that three colors once were considered to be characteristic and that some "Sardonyx gems are made up out of three stones cemented together so neatly that the fraud cannot be discovered...