Thulite

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Thulite is the translucent to opaque pink variety of zoisite, which is often mottled or streaked with gray or white quartz. The name thulite is derived from its discovery location, Norway, which was once called Thule. This gem is also called rosaline. Thulite is often cut en cabochon for jewelry manufacture or carved into ornaments.

Thulite Polished
Thulite Classification
Common Name Thulite
Species Zoisite
Thulite Optical Properties
Transparency Translucent - Opaque
Dispersion Strength: Weak Fire Value: 0.021
Refractive Index 1.691-1.700
Tolerance:(+0.005/-0.005)
Birefringence 0.008-0.013
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism Unobservable
Thulite Characteristic Physical Properties
Hardness 6-7
Streak White
Specific Gravity 3.100-3.450 Typical:3.350
Toughness Varies
Inclusions Thulite has white veining is due to calcite and the pink color is due to manganese.
Luster Vitreous, Pearly
Stability Good
Fracture Conchoidal, Uneven
Cleavage Perfect, in one direction, Good, in one direction
Thulite Chemistry & Crystallography
Chemical Name calcium aluminum silicate hydroxide
Chemical Formula Ca2Al3(SiO4)3(OH)
Crystal System Orthorhombic
Chemistry Classification Silicate

Thulite Colors

  • Multi-color Thulite Multi-color
  • Red Thulite Red
  • Pink Thulite Pink

Alternate Names

Rosaline, Unionite

Countries of Origin

United States of America (the); Unknown; Norway

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Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.