Fluor Spar.
This mineral occurs in many colors, often approaching the finer gems in appearance, and bearing the commercial names of false ruby, false emerald, false topaz, etc., etc., according to its color.
Fluor spar is brittle, 4 in hardness, has the specific gravity of 3.1 to 3.2, single refraction, is transparent to translucent, has a vitreous lustre, phosphoresces when heated, is attacked by acids, and melts before the blow-pipe. It is composed of:
| Fluorine | 48.7 |
| Calcium | 51.3 |
White, yellow, green, rose- and crimson-red, violet-blue, sky-blue, and brown, wine-yellow, greenish-blue, and gray are the colors of this many-tinted mineral.
Fluor spar is found in England, Norway, Baden, Nova Scotia, Thuringia, the Alps, Saxony, and the United States.
Large pieces of this mineral are made into beautiful vases and ornaments.
Hypersthene.
Handsome specimens of hypersthene or Labrador hornblende are used for ornamental purposes.
This mineral is found in crystalline masses, has the hardness of 6, specific gravity 3.3 to 3.4, lustre pearly to metallic. It is translucent to opaque, brittle, and fuses before the blow-pipe. It consists of: