QUARTZ

Due to its chemical simplicity, Quartz can found all over the world in one form or another. In its pure form it is Silicon Dioxide, chemical composition SiO₂ which is found in nature either as colourless crystals or in micro-crystalline masses, commonly referred to as Quartzite.

The addition at the molecular level of trace ions of other elements give rise to its range of colours and the hugely differing varieties of Quartz which include:
Amethyst:  Purple coloured due to Iron. Many gems are heat treated to bring out the colour.
Smoky Quartz:  Brown, greyish-brown to black Quartz whose colour is due to natural irradiation.
Citrine:   Yellow colour is usually the result of heat treatment of Amethyst or Smoky varieties, with natural stones being rare.
Rose Quartz:  Pink Quartz, usually with a hazy translucency, coloured by Iron, Titanium or Manganese. Transparent examples are hard to find.

Other varieties include the light green Prasiolte, which is not found in nature but is the result of heat-treatment of Amethyst or pale Citrine, and visual-effect Quartzes such as the chatoyant Tigers-Eye or Star-stones, the micro-crystalline Chrysocolla, Cornelian, Chrysoprase and all Agates and Jaspers, which you will find in a separate category on this website.