Plagioclase is a sub-series of the feldspar group.
Gemological Information for Plagioclase
Color: | Gray to Black for Labradorite, Yellow, Orange to Brown for Oligolcase |
Crystal Structure: | Monoclinic |
Refractive Index: | 1.599 to 1.568 Plagioclase |
Durability: | Poor |
Hardness: | 6 to 6.5 |
Family: | Feldspar |
Similar Stones: | Beryl, Quartz, Scapolite, Goldstone Glass |
Treatments: | Wax Impregnation, Irradiation |
Country of Origin: | Brazil, Madagascar, Norway, US, Russia |
Plagioclase Care
Ultrasonic Cleaning: | Never |
Steam Cleaning: | Never |
Warm Soapy Water: | Safe |
Chemical Attack: | Hydrofluoric Acid attacks quickly. Impurities may react to other acids. |
Light Sensitivity: | Stable |
Heat Sensitivity: | Can Crack, Fade and Cleave |
Sources
- Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 101-107.
- Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 122.
- Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 164-167.