184	NATURAL HISTORY OF GEMS.
	classes of their times. Of the two first, undisputed repre­sentatives are discovered amongst their remains ; of the third none whatever, if the Agate-vases (which also occur in the due relative proportion) be excluded. Pliny, however, could not have been mistaken as to the real character of the mineral ; for he states that Pompey brought it to Borne both in the rough and worked up into vases (lapides * et pocula) ; which he dedicated to the Capitoline Jupiter. Now Appian records that 2000 vessels of the "gem Onychitis" formed part of the treasures of Mithridates captured at Talaura, which shows that the Greek Onychitis (not Onyx) was the same as the Roman Murrhina, for Pliny expressly says that it was their con­quest of Mithridates that first set the Romans mad after gems and MuTrhina.t Inasmuch as the district producing the stone in its greatest perfection lay within the dominions of this king, it was to be expected he should have engrossed the finest specimens of the worked-up mineral. Imme­diately after this it came into general use in Borne for dishes, or rather plates for food (abaci escarii), a form for which it was best suited in consequence of the thinness of the layers. Pieces, however, were obtained of extraordinary superficial dimensions, for among the rarities displayed in Pompey's triumphal procession was a draught-board, four feet long by three wide, formed out of only two slabs