Gemological Information for Thulite

Color: Pink (Sometimes with White Streaks)
Crystal Structure Orthorhombic
Refractive Index: 1.691 to 1.700
Durability: Fair to Poor
Hardness: 6 to 7
Family: Zoisite
Similar Stones: Rhodonite, Hydrogrossular Garnet
Treatments: None Known
Country of Origin: Tanzania, Austria, Germany, Italy, Mexico, Switzerland, U.S.

Thulite Care

Ultrasonic Cleaning: Never
Steam Cleaning: Never
Warm Soapy Water: Safe
Chemical Attack: Hydrochloric and Hydrofluoric Acids Attack
Light Sensitivity: Stable
Heat Sensitivity: Jeweler's Torch may Fuse


  • Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 262-264.
  • Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 160.