Art Nouveau Orthoclase Feldspar (Moonstone) Pendant.
Art Nouveau Orthoclase Feldspar (Moonstone) Pendant.

Orthoclase is a mineral series in the feldspar group.

Gemological Information for Orthoclase Feldspar

Color:Colorless, White, Green, Orange, Yellow, Brown, Gray and Black
Crystal Structure:Monoclinic
Refractive Index:1.518 to 1.526
Durability:Not Very Durable
Hardness:6 to 6.5
Similar Stones:Chalcedony and Quartz
Treatments:Blue or Black Coating on Reverse
Country of Origin:Sri Lanka, Myanmar, India

Orthoclase Feldspar Care

Ultrasonic Cleaning:Never
Steam Cleaning:Never
Warm Soapy Water:Safe
Chemical Attack:Hydrofluoric Acid
Light Sensitivity:Stable
Heat Sensitivity:Can Crack or Cleave when Heated


  • Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 103-105.
  • Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 224.
  • Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 164.
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