Albite

Big Photo

Sri Lanka
1.59 carats
© Giovanni Scapin 2015

Albite is a plagioclase feldspar consisting of 90% or more of sodium-rich molecule.
The name Albite derives from Latin - albus, because its colour is usually pure white.
General Information
A variety or type of:Feldspar
Chemical Formula
NaAlSi
 
3
O
 
8
Michael O’Donoghue, Gems, Sixth Edition (2006)
Photos of natural/un-cut material from mindat.org
Albite Treatments
Irradiation may turn colourless material blue if lead and water impurities are present (see amazonite).
Physical Properties of Albite
Mohs Hardness6 to 6.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Specific Gravity2.60 to 2.65
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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TenacityBrittle
Michael O’Donoghue, Gems, Sixth Edition (2006)
Cleavage QualityPerfect
Michael O’Donoghue, Gems, Sixth Edition (2006) Perfect to excellent
FractureUneven,Conchoidal
Michael O’Donoghue, Gems, Sixth Edition (2006)
Optical Properties of Albite
Refractive Index1.525 to 1.542
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Optical CharacterBiaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.008 to 0.011
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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DispersionWeak
Michael O’Donoghue, Gems, Sixth Edition (2006)
Colour
Colour (General)Colourless, greenish, bluish, black (adularescent)
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,Pearly
Michael O’Donoghue, Gems, Sixth Edition (2006)
Fluorescence & other light emissions
Fluorescence (Short Wave UV)White, green
Michael O’Donoghue, Gems, Sixth Edition (2006)
Fluorescence (Long-Wave UV)Green
Michael O’Donoghue, Gems, Sixth Edition (2006)
PhosphorescenceGolden brown, green
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Albite
Crystal SystemTriclinic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
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Geological Environment
Where found:Found widely in greenschist facies metamorphic rocks. In igneous rocks, it
occurs principally in pegmatites and in alkali-rich rocks such as nepheline syenites and other feldspathoidal types. Common in spilites and keratophyres.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Albite information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Mogok Valley
Ted Themelis (2008) Gems & mines of Mogok
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