Smoky Quartz

Smoky Quartz is a brownish-black to greyish color variety of quartz. Cairngorm is the Scottish term for smoky quartz.

Smokey Quartz and Diamond Art Deco Lavaliere.

Smokey Quartz and Diamond Art Deco Lavaliere.

Gemological Information for Smoky Quartz

  
Color:Brown to Black or Smoky Grey
Crystal Structure:Hexagonal (Trigonal)
Refractive Index:1.544 to 1.553
Durability:Good
Hardness:7
Family:Quartz
Similar Stones:Andalusite, Tourmaline, Idocrase
Treatments:Quench Crackle, Irradiation, Heat Treatment and Coating or Backing
Country of Origin:Brazil, Scotland, India, Madagascar, Mexico, Srilanka, South Africa, Russia

Smoky Quartz Care

  
Ultrasonic Cleaning:Usually Safe
Steam Cleaning:Risky
Warm Soapy Water:Safe
Chemical Attack:Soluble in Hydrofluoric Acid and Ammonium Fluoride
Light Sensitivity:Usually Stable
Heat Sensitivity:May Fracture or Change Color

Sources

  • Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 187-190.
  • Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 283.
  • Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 116.