Clinozoisite

Clinozoisite was discovered in 1896 in Tyrol, Austria, and is named because of its monoclinic crystallography and resemblance to zoisite.

Clinozoisite is colourless, yellow, greenish or pale rose-red mineral similar to Epidote, but containing little iron.

Clinozoisite Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 
 
 

Clinozoisite Gemstones by Size

This table shows distribution of Clinozoisite gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.15 cts
Heaviest:3.69 cts
Average:0.66 cts
Total photos:26
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0.15ct to 0.50ct0.50ct to 0.86ct0.86ct to 1.21ct1.21ct to 1.57ct1.57ct to 1.92ct1.92ct to 2.27ct2.27ct to 2.63ct2.63ct to 2.98ct2.98ct to 3.34ct3.34ct to 3.69ct
General Information
Chemical Formula
Ca
 
2
Al
 
3
(SiO
 
4
)
 
3
(OH)
Walter Schumann, Gemstones of the world (2001)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Clinozoisite
Mohs Hardness6 to 7
Walter Schumann, Gemstones of the world (2001)
Specific Gravity3.21 to 3.38
Michael O’Donoghue, Gems, Sixth Edition (2006)
Cleavage QualityPerfect
Michael O’Donoghue, Gems, Sixth Edition (2006)
Optical Properties of Clinozoisite
Refractive Index1.670 to 1.734
Michael O’Donoghue, Gems, Sixth Edition (2006) RI for the alpha, beta and gamma rays is 1.670–1.715, 1.675–1.725 and 1.690–1.734
Optical CharacterBiaxial/+
Michael O’Donoghue, Gems, Sixth Edition (2006)
Birefringence0.005 to 0.015
Michael O’Donoghue, Gems, Sixth Edition (2006)
Colour
Colour (General)Yellow to yellow-brown, colourless, greenish, pink.
Walter Schumann, Gemstones of the world (2001)
More from other references
Causes of ColourGreen (tawmawite), Cr3+ in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent,Translucent
Walter Schumann, Gemstones of the world (2001)
More from other references
LustreVitreous
Walter Schumann, Gemstones of the world (2001)
Crystallography of Clinozoisite
Crystal SystemMonoclinic
Michael O’Donoghue, Gems, Sixth Edition (2006)
HabitElongated prismatic crystals
Michael O’Donoghue, Gems, Sixth Edition (2006)
Geological Environment
Where found:Typically in low- to medium-grade regionally metamorphosed igneous and sedimentary rocks, as well as in contact metamorphosed calcium-rich sediments; an alteration product of plagioclase feldspars (saussuritization).
Anthony et al, Handbook of Mineralogy (2001)
Further Information
Mineral information:Clinozoisite information at mindat.org
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