Thulite

Big Photo

Tanzania
4.29 carats
© Palagems

Dense, opaque, pink or mottled pink-and-white variety of Zoicite that was first found in Norway and named after Thule, the ancient name for that country. Thulite is used as a gemstone and carving material in the manufacture of jewellery and ornamental objects.

Thulite Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
General Information
A variety or type of:Zoisite
Chemical Formula
Ca
 
2
Al
 
3
(SiO
 
4
)(Si
 
2
O
 
7
)(O,OH)
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
Photos of natural/un-cut material from mindat.org
Physical Properties of Thulite
Mohs Hardness6 to 7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity3.1
Arthur Thomas, Gemstones (2009)
Cleavage QualityPerfect
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Thulite
Refractive Index1.695(+/-)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterBiaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.006 to 0.013
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Pink to red variety of zoisite, often mottled white and gray
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Causes of ColourPink, Mn3+ in presumably octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyOpaque
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Thulite
Crystal SystemOrthorhombic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
HabitMassive
Arthur Thomas, Gemstones (2009)
Further Information
Mineral information:Thulite information at mindat.org
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