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Dumortierite

Big Photo

Madagascar
3.63 carats
© Rarestone.com

Dumortierite Gemstones by Colour

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

Dumortierite Gemstones by Size

This table shows distribution of Dumortierite 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:1.10 cts
Heaviest:5.58 cts
Average:3.26 cts
Total photos:11
Do you have a larger Dumortierite? Why not upload a photo?
1.10ct to 1.55ct1.55ct to 2.00ct2.00ct to 2.44ct2.44ct to 2.89ct2.89ct to 3.34ct3.34ct to 3.79ct3.79ct to 4.24ct4.24ct to 4.68ct4.68ct to 5.13ct5.13ct to 5.58ct
General Information
Chemical Formula
Al
 
7
(BO
 
3
)(SiO
 
4
)
 
3
O
 
3
Michael O’Donoghue, Gems, Sixth Edition (2006)
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Physical Properties of Dumortierite
Mohs Hardness7
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Specific Gravity3.31
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Cleavage QualityNone
Arthur Thomas, Gemstones (2009)
FractureUneven
Arthur Thomas, Gemstones (2009)
Optical Properties of Dumortierite
Refractive Index1.669 to 1.723
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Rare red-brown crystals +/- 1.669More from other references
Optical CharacterBiaxial/-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Birefringence0.011 to 0.037
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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PleochroismStrong trichroism for rare red-brown crystals: black - red brown - brown
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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DispersionNil
Arthur Thomas, Gemstones (2009)
Colour
Colour (General)Blue, green, blue-green, brown, red-brown, reddish, violet
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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TransparencyTransparent,Translucent,Opaque
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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LustreVitreous
Arthur Thomas, Gemstones (2009) Dull
Fluorescence & other light emissions
Fluorescence (Short Wave UV)Inert to chalky blue, often intergrown with quartz
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Dumortierite
Crystal SystemOrthorhombic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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HabitCommonly fibrous aggregate
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Geological Environment
Where found:Dumortierite occurs in pegmatite veins or in aluminium-rich regionally metamorphosed rocks.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Dumortierite information at mindat.org
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