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Thulite



Thulite

Thulite from Leksvik, Norway.
General
CategoryMineral Variety
Chemical formula(Ca2Al3(SiO4)(Si2O7)O(OH)
Identification
ColorPink
Crystal habitMassive
Crystal systemOrthorhombic
CleavagePerfect {010} imperfect {100}
FractureUneven to conchoidal
Mohs Scale hardness6.5
LusterVitreous, pearly on cleavage surfaces
Refractive index1.69-1.70
Optical Propertiesbiaxial positive
Birefringence0.006-0.018
PleochroismPresent, dichroism or trichroism depending on color.
StreakWhite or colorless
Specific gravity3.10-3.38

Thulite (sometimes called rosaline) is an opaque, massive pink manganese rich variety of the mineral zoisite. Thulite is often mottled with white calcite and occurs as veins and fracture fillings transecting many types of rock. In mineralogical literature, thulite may sometimes refer to any pink zoisite.

Additional recommended knowledge

Thulite was first discovered in Lom, Norway in 1820. It is named after the mythical island of Thule in the belief that the island is Norway. Thulite is used as a gemstone and carving material in the manufacture of jewelery and ornamental objects.

Thulite is also found in the Austrian Tyrol, in Mitchell County, North Carolina, and in Western Australia. A new, more recent find of high quality thulite was discovered near Riverside in Okanogan County, Washington, USA.

References

  • Mindat with location data
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Thulite". A list of authors is available in Wikipedia.
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