QUARTZ. In 1772 Cronstedt wrote in his work on Mineralogy: “I shall adopt the name of Quartz in English as it has already general access in other European Languages.” There seems to be little doubt regarding the origin of the word which comes from the German QUARZ. Professor James D. Dana gives the Quartz varieties under the following heads:—
1. Vitreous. Distinguished by their glassy fracture.
2. Chalcedonic. Having a sub-vitreous or a waxy lustre and generally translucent.
3. Jaspery Cryptocrystalline. Having barely a glimmering lustre or none, and opaque.
To the first belong: Amethyst, Aventurine Quartz, Cairngorm, Citrine, Ferruginous Quartz, False or Spanish Topaz, Milk Quartz, Prase, Rock Crystal, Rose Quartz, Smoky Quartz.
To the second belong: Chalcedony, Chrysoprase, Sard, Carnelian, Agate, Onyx, Cat’s Eye, Flint, Hornstone, Chert, Plasma.
To the third belong: Jasper, Heliotrope or Bloodstone, Lydian Stone, Touchstone, Basanite, Silicified Wood, Pseudomorphous Quartz, etc.
Opal is a near ally to Quartz which is a most useful as well as an ornamental substance.
RUBELLITE. (See [TOURMALINE].)
RUBICELLE. (See [SPINEL].)