or ACANTETA, in Natural History, a name given by the ancients to the purest and finest kind of rock crystal: They used the crystal in many ways; sometimes engraving on it, and sometimes forming it into vases and cups, which were held next in value to the vasa muraria of those times. The crystal they obtained from the island of Cyprus was much esteemed; but often faulty in particular parts, having hairs, cracks, and foulnesses, which they called falsis, in the middle of the large pieces. Pliny tells us, that when it was used for engraving on, the artist could conceal all these blemishes among the strokes of his work; but when it was to be formed into cups or precious vases, they always chose the acentetum which had no flaws or blemishes.