| General Information |
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| A variety or type of: | Feldspar |
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| Chemical Formula | Michael O’Donoghue, Gems, Sixth Edition (2006) |
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| Physical Properties of Anorthite |
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| Mohs Hardness | 6 to 6.5Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Specific Gravity | 2.77Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Tenacity | BrittleMichael O’Donoghue, Gems, Sixth Edition (2006) |
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| Cleavage Quality | PerfectUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Fracture | Uneven,ConchoidalMichael O’Donoghue, Gems, Sixth Edition (2006) |
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| Optical Properties of Anorthite |
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| Refractive Index | 1.575 to 1.588Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Optical Character | Biaxial/-Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Birefringence | 0.013Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Colour |
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| Colour (General) | Usually white, grey or colourless but can be pale shades of other colours. Occassionally reddishMichael O’Donoghue, Gems, Sixth Edition (2006) More from other references |
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| Transparency | Transparent,TranslucentUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Lustre | Vitreous,Dull (Earthy)Michael O’Donoghue, Gems, Sixth Edition (2006) |
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| Fluorescence & other light emissions |
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| Fluorescence (Long-Wave UV) | Cream, pale brownMichael O’Donoghue, Gems, Sixth Edition (2006) |
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| Crystallography of Anorthite |
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| Crystal System | TriclinicUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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| Geological Environment |
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| Where found: | Anorthite is usually found in contact metamorphic limestones and as a constituent in some basic calc-alkali plutonic rocks and lavas.Michael O’Donoghue, Gems, Sixth Edition (2006) |
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| Further Information |
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| Mineral information: | Anorthite information at mindat.org |
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