HYACINTH or JACINTH, in mineralogy, a variety of zircon (q.v.) of yellowish red colour, used as a gem-stone. The hyacinthus of ancient writers must have been our sapphire, or blue corundum, while the hyacinth of modern mineralogists may have been the stone known as lyncurium (Xuyaovpcov). The He brew word leshem, translated ligure in the A.V. (Exod. xxviii. 19), from the Xcyvpcov of the Septuagint, appears in the R.V. as jacinth, but with a marginal alternative of amber; both may be reddish yellow, but their indentification is doubtful. Most of the gems known in trade as hyacinth are only garnets, generally the deep orange-brown hessonite or cinnamon-stone ; and the stones known as Compostella hyacinths are simply ferruginous quartz from Santiago de Compostella, Spain. Hyacinth is not a common mineral. It occurs, with other zircons, in the gem-gravels of Ceylon, and very fine stones have been found as pebbles at Mudgee, New South Wales. Crystals of zircon, with all the typi cal characters of hyacinth, occur at Expailly in Central France, but they are not large enough for cutting. (L. J. S.)