| General Information |
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| A variety or type of: | Spinel |
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| Chemical Formula | Gemdat.org, Management Team (2012) |
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| Physical Properties of Pleonaste |
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| Mohs Hardness | 8Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Specific Gravity | 3.80Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Cleavage Quality | NoneMichael O’Donoghue, Gems, Sixth Edition (2006) |
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| Optical Properties of Pleonaste |
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| Refractive Index | 1.780Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Optical Character | IsotropicUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Colour |
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| Colour (General) | BlackUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Transparency | OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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| Lustre | VitreousArthur Thomas, Gemstones (2009) |
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| Crystallography of Pleonaste |
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| Crystal System | IsometricHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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| Habit | Octahedra though some specimens may show dodecahedron or cube faces.Michael O’Donoghue, Gems, Sixth Edition (2006) |
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| Further Information |
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| Mineral information: | Pleonaste information at mindat.org |
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| Significant Gem Localities |
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| Madagascar | | |
| Pezzotta (1999) |
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