216                 NATURAL HISTORY OF GEMS.
	solite, the sard, and the jasper :" and again the statement which follows, taken from Zenothemis, that the Indian Onyx presented " many different colours ; fiery, black, and horny, surrounded by opaque white veins like an eye;" ami, further, that of Satyrus, that the same species was " flesh-coloured, having one part of the chrysolite, another of the amethyst" (xxxvii. 24). For these banded Agates, the produce of India alone, cut across their layers, often present the most beautiful and vivid colours, mimicking the Topaz, the Garnet, and the Jacinth, in strongly-contrasted juxta­position. Similarly the Sardonyx of the Greeks equally differed in appearance, though not in species, from that of the imperial Romans. Pliny quotes (xxxvii. 23) several Greek authorities, to the effect that by the Indian Sardonyx they understood a Sard with a white layer (candor in sarda), and both colours transparent. The opaque kind, which in Pliny's times he notes had engrossed the designation, they termed the Blind, and apparently held it in no esteem. Their Sardonyx was, in fact, the same evenly-stratified union of Calcedony and Jasper as their Üíí÷éïí ; with the distinction that its colours were white and red, not white and black : for red was the proper and indispensable character of the Sard. Pliny proceeds to give the reason for its uni­versal use as a signet-stone amongst the Greeks upon its first introduction from India : it was because the soft wax used for sealing did not adhere to the engravings in this ma­terial, in which respect the Sardonyx excelled almost every other gem. He uses the word " initio," at first, in evident allusion to the total neglect of the gem in this capacity in his own times. For amongst the purely Greek and Etruscan works that Tricoloured Agate is frequent which presents its bands in sard-red and white as well as in the dark-brown and white of the original ïíí÷éïí. This valuable property of the gem, its non-adhesion to the wax, is a sufficient