Sinhalite

Big Photo

Sri Lanka
10.23 carats
© Rarestone.com

The name Sinhalite is derived from the Sanskrit name for Sri Lanka - Sinhala, where it was discovered in 1952. It is a rare mineral which until recently was found only in this country.

Nowadays Sinhalite is also found in Mogok, Burma and pale-pink to brownish-pink crystals has been reported from Tanzania. Rough, well crystallized sinhalite up to sizes of 20 grams are being found in Madagascar.

Sinhalite Gemstones by Colour

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

Sinhalite Gemstones by Size

This table shows distribution of Sinhalite 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:0.28 cts
Heaviest:16.39 cts
Average:4.96 cts
Total photos:14
Do you have a larger Sinhalite? Why not upload a photo?
0.28ct to 1.89ct1.89ct to 3.50ct3.50ct to 5.11ct5.11ct to 6.72ct6.72ct to 8.34ct8.34ct to 9.95ct9.95ct to 11.56ct11.56ct to 13.17ct13.17ct to 14.78ct14.78ct to 16.39ct
General Information
Chemical Formula
MgAlBO
 
4
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Sinhalite
Mohs Hardness6 to 7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity3.46 to 3.50
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
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FractureConchoidal
Arthur Thomas, Gemstones (2009)
Optical Properties of Sinhalite
Refractive Index1.665 to 1.712
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Optical CharacterBiaxial/-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Birefringence0.036 to 0.042
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) DoublingMore from other references
PleochroismTrichroism: green - light brown - dark brown
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Dispersion0.018
Walter Schumann, Gemstones of the world (2001)
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Colour
Colour (General)Colourless, yellow-brown, green-brown, brown
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Causes of ColourBrown, O2-Fe3+ charge transfer and Fe2+ in octahedral coordination
W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011)
TransparencyTransparent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
LustreVitreous
Arthur Thomas, Gemstones (2009)
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
Crystallography of Sinhalite
Crystal SystemOrthorhombic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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HabitVery rare; grains
Walter Schumann, Gemstones of the world (2001)
More from other references
Geological Environment
Where found:Sinhalite occurs in boron-rich skarns at the contact of limestones with granite or gneiss; most gem sinhalite is found as alluvial pebbles.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Inclusions in Sinhalite
Sillimanite needles - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 4
Needle-like to fibrous crystals - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 19
Further Information
Mineral information:Sinhalite information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
        • Mogok Valley
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
Ted Themelis (2008) Gems & mines of Mogok
  • Sagaing Region (Sagaing Division)
    • Katha District
      • Wuntho Township
Ted Themelis (2008) Gems & mines of Mogok
Sri Lanka
 
  • Central Province
  • Sabaragamuwa Province
    • Ratnapura District
Natural History Museum Vienna collection
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