Montebrasite


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Big Photo

Brazil
2.56 carats
© Rarestone.com

Montebrasite is named after its discovery locality, at Montebras, Creuse, France.

Montebrasite forms attractive, colourless, bright yellow-green, sometimes blue, pink and pale brown, equant to short-prismatic crystals, twinning is common.

Montebrasite Gemstones by Colour

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

Montebrasite Gemstones by Size

This table shows distribution of Montebrasite 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:2.56 cts
Heaviest:21.55 cts
Average:7.67 cts
Total photos:6
Do you have a larger Montebrasite? Why not upload a photo?
2.56ct to 4.46ct4.46ct to 6.36ct6.36ct to 8.26ct8.26ct to 10.16ct10.16ct to 12.06ct12.06ct to 13.95ct13.95ct to 15.85ct15.85ct to 17.75ct17.75ct to 19.65ct19.65ct to 21.55ct
General Information
Chemical Formula
LiAl(PO
 
4
)(OH,F)
Walter Schumann, Gemstones of the world (2001)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Montebrasite
Mohs Hardness5.5 to 6
Walter Schumann, Gemstones of the world (2001)
More from other references
Specific Gravity2.98 to 3.10
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
TenacityBrittle
Anthony et al, Handbook of Mineralogy (2001)
Cleavage QualityPerfect
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
FractureUneven,Sub-Conchoidal
Anthony et al, Handbook of Mineralogy (2001)
Optical Properties of Montebrasite
Refractive Index1.578 to 1.646
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterBiaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Birefringence0.020 to 0.030
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Colourless, yellowish, light green, light blue, white, pink.
Walter Schumann, Gemstones of the world (2001)
More from other references
TransparencyTransparent
Walter Schumann, Gemstones of the world (2001)
More from other references
LustreVitreous
Walter Schumann, Gemstones of the world (2001)
More from other references
Fluorescence & other light emissions
Fluorescence (Long-Wave UV)Inert to weak green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
PhosphorescenceMay phosphoresce light blue to LW and SW
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Crystallography of Montebrasite
Crystal SystemTriclinic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
HabitCrystals typically equant, may be short to long prismatic, to 10 cm; as coarse cleavable or blocky to rounded nodular masses.
Anthony et al, Handbook of Mineralogy (2001)
Geological Environment
Where found:A late primary and secondary mineral in zoned granite pegmatites; may be an ore of lithium.
Anthony et al, Handbook of Mineralogy (2001)
Further Information
Mineral information:Montebrasite information at mindat.org
Significant Gem Localities
Brazil
 
  • Minas Gerais
    • Divino das Laranjeiras
Myanmar
 
  • Mandalay Region
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Kyauk-Pyat-That
Ted Themelis (2008) Gems & mines of Mogok
        • Mogok Valley
Ted Themelis (2008) Gems & mines of Mogok
        • Pein-Pyit (Painpyit; Pyan Pyit)
Ted Themelis (2008) Gems & mines of Mogok
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