SARDONYX, a precious stone consisting of a mixture of the chalcidony and carnelian, sometimes in strata, but at other times blended together. It is found, 1. Striped with white and red strata, which may be cut in cameo as well as the onyx. 2. White with red dendritic figures, greatly resembling the mocha-stone; but with this difference, that the figures in the sardonix are of a red colour, in the other black. There is no real difference, excepting in the circumstance of hardness, between the onyx, carnelian, chalcidony, sardonix, and agate, notwithstanding the different names bestowed upon them. Mongex informs us, that the yellow, or orange-coloured agates, with a wavy or undulating surface, are now commonly called sardonix. See CARNELIAN and ONYX.