Mohave County miner., 1884-06-01
Quartz.

The crystals of quartz occur 1T
 very many forms. Among the crys
 talline varieties the rock crystal is
 colorless and transparent. It occurs
 in line crystals in most mining dis tricts, but is rarely abundant. The
 luster of the finest specimens Is rath-
 CT adamantine than vitreops and ap-
 breaches that of the diamond. The
 California diamond" is a familiar example. They may, however, be readily distinguished from real dia-
 monds by their difference of crystal
 line form and their inferior hardness and specific gravity. Amethyst is a purple or violet crystalline variety which occurs in many localities. Citrine or false topaz is yellow va riety which sometimes occurs in fine
 crystals. It may be distinguished from the real topaz by the difference oE crystalline form, amount of cleav- age and inferior hardness. Ferru ginous quartz is reddish brown rath- CT than yellow and often nearly opa- que, It is ordinary quartz much colored with oxide of iron of which it occasionally contains as much as five per cent.
 Cairngorm or smoky quartz also occurs n crystals. Morton IS a black crystalized quartz which occurs in Scotland and in many of the Cornish mlues. Siderite or sapphire quartz is of rich indigo-blue color, and occurs in impure limestone at Coll or Salzbnrg. Rose quartz in some localities is quite abundant. Milky quartz is nearly opaque, and is the color of milk, sometimes crystalline, but oftener massive It occurs in many mines, usually in small quan titles. Cotterite Is a variety from Ireland, possessing brilliant pearly lustre. Sugary quartz IS a granular and somewhat friable and massive variety. Floatstone is a cellular va riety. FIbrous quartz or cross course spar is made up of a multitude of imperfect prisms. pressed confusedly against each other side by side.
 The crypto-crystalline or amor phous varieties are several.
 Chalcedony is milkwhlte, yellow, brown or pale lavender blue. Flint appears to be a variety of chaIcednhy. having the same hardness, specific gravity and chemical composition. etc, but It differs ln some respects. Carnelian is a beautiful reddish brown variety, much used for per sonal ornaments. Agate is complex stone composed of chalce dony, jasper and sometimes ordinary quartz. The chief varieties of agate are onyx which IS composed of alternate bands and sardonyx, which includes red dish or yellowish bands. Hehotrope or bloodstone is composed of green plasma with red jasper. Plasma is dark green and nearly opaque. Chry is apple green; the color ap pears to be due to oxide of nickel Prase is dull green and massive.
 Jasper IS an opaque massive varie- ty colored by oxide of iron or other foreign substances. It is sometimes banded of different colors when 1t is called ribbon jasper. Basanite or Lydian stone is a dark variety of jasper Many other varieties of quartz have been distinguished by speclal names, many of them more or less local in their character. Sagentic quartz is simply quartz which inclo ses other minerals or needles cross ing each other. such as rutlle, tour maline and the like. Cats-eye quartz is opalescent from the presence of their fibers of abestos. Avanturine quartz contains flakes or spangles of mlca, GSorite, hematite or other LaIba, f E4od ,,oi,cnrsi- IcwI,uSroe