258	ONYX.
	times eyes, then was the stone the Onyx. But if the various colours of the stone lay in regular strata one over the other, then it became the Sardonyx." That the concentric arrangement of the veins was the peculiar distinction of the Onyx, appears from Pliny's brief notice (xxxvii. 71) of its variety now known as the Eye-Onyx : " Triophthalmus cum Onyche nascitur, très hominis oculos simul exprimens." The fact being that in Pliny's age the name no longer bore the same acceptation as when Theophrastus used it, but was certainly applied to the stone now called the Agate. This is the only way of understanding the passages already quoted from Sotacus and Zenothemis, as to its various colours surrounded by white veins like an eye, and these again sometimes traversed by other white veins running athwart them ; and the remark of the former that " the true Onyx presents nu­merous and differently-coloured veins with milk white zones, the transition of colours between them being perfectly indescribable, yet all blending into one harmonious whole, highly charming to the eye." It is singular, however, that Pliny should give no definition in his own terms, of what the Romans understood by the designation Onyx, but should have contented himself with citing these obscure descriptions of earlier and Grecian authors, being apparently himself in doubt as to the exact species of gem to which they referred. Epiphanius, with his usual ignorance, confounds the marble with the gem Onyx : " Twelfth Stone (in the Eationale) the Onyx : this hath its colour exceeding yellow (ξανθην). It is said that the wives of the kings (of Persia) and of the nobles take great delight in this stone, and have it made into drinking-cups for their own use. Besides this, there are other sorts, similarly called Onychytes, resembling yellow bee's-wax. And some pre­tend that such are formed by the condensation of water dropping. These are called Onychites (nail-stones) in natural history, be­cause the finger-nail in well-bred persons is made up of two colours, a marble-white coupled with the appearance of the blood underneath, through the substance of the nail. Some, however, occasionally term marble Onychites, from the mode of testing it (by the finger-nail), or from the purity of its whiteness ; but they are in error."