Smoky quartz

Smoky quartz is a macrocrystalline variety of quartz, meaning the size of the individual grains or crystals are distinguishable with the naked eye. Some of the other macrocrystalline quartz varieties are Amethyst, Ametrine, Cat's-eye Quartz, Citrine, Phantom Quartz, Rock Crystal, Rose Quartz and Rutilated Quartz..

Color
Smoky quartz may vary in color from brown to black to gray.

Origin
Smoky quartz may be found in Brazil, Switzerland, the Himalayas, Mexico and the United States.