Esperite
Esperite is named after Esper Signius Larsen, Jr., Professor of Geology, Harvard University.
Esperite has a white, greasy appearance in daylight and shows brilliant yellow green fluorescence under shortwave ultraviolet light.
| General Information |
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| Chemical Formula | Anthony et al, Handbook of mineralogy (2001) |
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| Physical Properties of Esperite |
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| Mohs Hardness | 5 to 5.5Anthony et al, Handbook of mineralogy (2001) |
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| Specific Gravity | 4.28 to 4.42Anthony et al, Handbook of mineralogy (2001) |
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| Cleavage Quality | Distinct,PoorAnthony et al, Handbook of mineralogy (2001) |
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| Fracture | ConchoidalAnthony et al, Handbook of mineralogy (2001) |
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| Light Sensitivity | Darkens on exposure to lightAnthony et al, Handbook of mineralogy (2001) |
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| Optical Properties of Esperite |
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| Refractive Index | 1.760 to 1.774Anthony et al, Handbook of mineralogy (2001) |
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| Optical Character | Biaxial/-Anthony et al, Handbook of mineralogy (2001) |
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| Colour |
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| Colour (General) | WhiteAnthony et al, Handbook of mineralogy (2001) |
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| Transparency | OpaqueAnthony et al, Handbook of mineralogy (2001) |
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| Lustre | Greasy,Dull (Earthy)Anthony et al, Handbook of mineralogy (2001) |
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| Fluorescence & other light emissions |
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| Fluorescence (Short Wave UV) | Brilliant yellow fluorescenceAnthony et al, Handbook of mineralogy (2001) |
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| Crystallography of Esperite |
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| Crystal System | MonoclinicAnthony et al, Handbook of mineralogy (2001) |
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| Habit | Granular aggregates, massive, to 9 cm.Anthony et al, Handbook of mineralogy (2001) |
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| Geological Environment |
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| Where found: | In a metamorphosed stratiform zinc orebody.Anthony et al, Handbook of mineralogy (2001) |
| Further Information |
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| Mineral information: | Esperite information at mindat.org |
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| Significant Gem Localities |
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