General Information |
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Chemical Formula | Michael O’Donoghue, Gems, Sixth Edition (2006) More from other references |
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Physical Properties of Ludlamite |
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Mohs Hardness | 3 to 4Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Specific Gravity | 3.1 to 3.2Walter Schumann, Gemstones of the world (2001) More from other references |
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Cleavage Quality | PerfectUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Fracture | UnevenArthur Thomas, Gemstones (2009) |
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Optical Properties of Ludlamite |
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Refractive Index | 1.653 to 1.693Ulrich 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 | 0.040Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Pleochroism | NilArthur Thomas, Gemstones (2009) |
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Dispersion | Relatively weakArthur Thomas, Gemstones (2009) |
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Colour |
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Colour (General) | Light- to apple-green, colourlessWalter Schumann, Gemstones of the world (2001) More from other references |
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Transparency | TransparentUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Lustre | VitreousArthur Thomas, Gemstones (2009) |
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Crystallography of Ludlamite |
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Crystal System | MonoclinicUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
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Habit | PrismaticMichael O’Donoghue, Gems, Sixth Edition (2006) More from other references |
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Geological Environment |
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Where found: | Occurs in granite pegmatites, resulting from the alteration of primary phosphatesMichael O’Donoghue, Gems, Sixth Edition (2006) |
Further Information |
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Mineral information: | Ludlamite information at mindat.org |
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Significant Gem Localities |
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| UK | |
| | | USA | |
- Blackbird Mining District
| Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 425 |
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