Hiddenite is the strongly pleochroic, bright green variety of spodumene. First discovered in North Caroline by W. E. Hidden in 1879.

Gemological Information For Hiddenite

Color: Green
Crystal Structure Monoclinic
Refractive Index: 1.662 to 1.676
Durability: Poor
Hardness: 6.5 to 7
Similar Stones: Tourmaline, Peridot, Beryl
Treatments: Irradiation
Country of Origin: Afghanistan, Madagascar

Hiddenite Care

Ultrasonic Cleaning: Never
Steam Cleaning: Never
Warm Soapy Water: Safe
Chemical Attack: Reacts slowly to Hydrofluoric Acid
Light Sensitivity: Irradiated Green fades quickly
Heat Sensitivity: Sensitive


  • Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 229-231.
  • Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 154-155.
  • Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 114.