| General Information |
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| Chemical Formula | Anthony et al, Handbook of mineralogy (2001) |
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| Physical Properties of Jacobsite |
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| Mohs Hardness | 5.5 to 6.5Anthony et al, Handbook of mineralogy (2001) |
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| Specific Gravity | 4.76 to 5.03Anthony et al, Handbook of mineralogy (2001) |
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| Optical Properties of Jacobsite |
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| Optical Character | IsotropicAnthony et al, Handbook of mineralogy (2001) |
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| Colour |
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| Colour (General) | Black to brownish black; grayish white with olive tint in reflected light, with brown internal reflections.Anthony et al, Handbook of mineralogy (2001) |
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| Transparency | Translucent,OpaqueAnthony et al, Handbook of mineralogy (2001) |
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| Lustre | Dull (Earthy),Metallic,SubmetallicAnthony et al, Handbook of mineralogy (2001) |
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| Crystallography of Jacobsite |
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| Crystal System | IsometricAnthony et al, Handbook of mineralogy (2001) |
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| Habit | Rarely in octahedral crystals, to 4 mm, which may exhibit exsolved hausmannite or galaxite; coarse to fine granular, massive.Anthony et al, Handbook of mineralogy (2001) |
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| Geological Environment |
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| Where found: | A primary mineral or an alteration product of other manganese-bearing minerals in some metamorphosed manganese deposits.Anthony et al, Handbook of mineralogy (2001) |
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| Further Information |
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| Mineral information: | Jacobsite information at mindat.org |
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