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Chemical Formula | Mn2SiO4 |
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Composition | Manganese silicate, sometimes with some magnesium and zinc. Forms a series with Forsterite. |
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Variable Formula | (Mn,Mg,Zn)2SiO4 |
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Color | Gray, grayish-green, brown, reddish-brown, pink |
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Streak | Light gray |
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Hardness | 6 |
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Crystal Forms and Aggregates |
(Orthorhombic) Occurs as rounded and fractured crystals, which are short prismatic. Also occurs grainy, massive, and in large cleavage fragments. |
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Transparency | Translucent. Rarely transparent. |
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Specific Gravity | 4.0 - 4.1 |
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Luster | Vitreous, greasy |
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Cleavage | 2,1 ; 3,1- forming a 90º angle |
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Fracture | Conchoidal to uneven |
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Tenacity | Brittle |
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In Group | Silicates ; Nesosilicates |
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Striking Features | Cleavage angles, color, and hardness |
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Popularity (1-4) | 3 |
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Prevalence (1-3) | 3 |
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Demand (1-3) | 3 |
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Distinguishing Similar Minerals |
Willemite - different cleavage, fluoresces bright green |
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Commonly Occurs With |
Quartz, Calcite, Rhodonite, Spessartine |
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Noteworthy Localities |
The most famous localities for this mineral are Franklin, Ogdensburg, and Sparta, all in Sussex Co., New Jersey. Tephroite is also found in Langban, Sweden. |
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Picture Icon Links |
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Picture Links | Sorry. No Images currently available. |
