Jacinth

Jacinth, or HYACINTH (Ital. giacinto, Lat. hyacinthus), a transparent, bright-coloured variety of Zircon (q.v.), of various shades of red, passing into orange and poppy-red. A perfect stone has a peculiar golden lustre mixed with its rich orange, and would formerly have fetched a high price; but the jacinth is no longer in fashion. By the ancients it was highly prized, and many fine intagli were executed in it, notwithstanding its hardness, which exceeds that of chalcidony and its varieties. Antique intagli in jacinth, however, almost invariably exhibit a somewhat rubbed or worn surface, which is believed to be due to the somewhat porous texture of the gem. Jacinth occurs in many basalts, tuffs, and some granitoid plutonic rocks, as, for example, near Expailly in Auvergne, and at Unkel on the Rhine, in Bohemia, Saxony, the Tyrol, Norway, the Urals, Greenland, &c. It is likewise met with in the form of granules and rounded crystals in the beds of certain streams, and in alluvial deposits, as near Expailly, in the Iszerwiese, and in certain streams in Ceylon. The jacinth or hyacinth of jewellers is not a zircon at all, but some variety of garnet—generally Cinnamon-stone (q.v.); and sometimes ferruginous quartz, which, from its abundance in gypsum at Compostella, in Spain, is called Hyacinth of Compostella.—Jargon is the name given by the Singhaless to another variety of zircon. It is usually gray or colourless, but often shows more or less ill-defined tinges of green, blue, red, and yellow. The surfaces of the crystals have a lustre almost rivalling that of the diamond. It was at one time supposed to be an inferior variety of the diamond, and is still occasionally sold as such.