Thulite
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Description
A pale to deep pink translucent Zoisite stone in which manganese replaces up to 2 % of the calcium. Thulite was discovered near Telemark, Norway and named for Thule, an old name for Norway. It is usually mottle with white, gray, or translucent regions of calcite and quartz. The stone has been used as a gemstone when polished as a cabochon.
Synonyms and Related terms
zoisite; rosaline; unionite
Physical and Chemical Properties
- Cleavage = perfect in one direction
- Luster = vitreous
- Fracture = conchoidal to uneven
- Streak = white or gray
- Fluorescence = may have fluorescence in SW due to calcite inclusions
- Pleochroism = present; and possibly dichroism or trichroism depending on color
| Mohs Hardness | 6.0 - 6.5 |
|---|---|
| Density | 3.1-3.4 g/ml |
| Refractive index | 1.691 - 1.700 |
| Birefringence | 0.006 - 0.018 |
Resources and Citations
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Wikipedia Thulite Accessed Dec 2022
- Mineralogy Database: Zoisite
- Gemopedia: Thulite (Accessed Dec 2022)