Crystalline Quartz Varieties

  1. Rock Crystal. Colorless quartz, commonly in distinct crystals.
  2. Amethyst. Quartz colored purple or violet, often crystallized.
  3. Rose Quartz; Usually massive, color a rose-red or pink. Often fades somewhat on exposure to light.
  4. Smoky Quartz.  Cairngorm Stone. Crystallized quartz of a smoky yellow to brown and almost black color. Named cairngorm from the locality of Cairngorm in Scotland.
  5. Citrine. Light yellow in color.
  6. Milky Quartz. Milky white in color and nearly opaque. Sometimes with greasy luster.
  7. Cat’seye. A stone, which when cut in a round shape (en cabochon) exhibits an opalescent or chatoyant effect, as it is termed, is called a cat’s-eye. Quartz among other minerals gives at times this effect which is due either fibrous inclusions or to a fibrous structure of the quartz itself. The latter is seen in the tiger’s – eye, a yellow fibrous quartz form South Africa, which is pseudomorphic after another fibrous mineral. Crocidolite.
  8. With Inclusions. Many other minerals occur at times as inclusions in quartz. Rutilated quartz has fine needles of rutile penetrating it. Tourmaline and other minerals are found in quartz in the same way. Aventurine is quartz including brilliant scales of hematite or mica. Liquids and gases at times occur as inclusions; both liquid and gaseous carbon dioxide exist in some quartz.