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| Manganite
is named in allusion to its manganese content.
| Discovered
in 1827;
IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Mn3+O(OH) |
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Manganese
Oxide Hydroxide |
Molecular
Weight: |
87.94 gm
|
Composition: |
Manganese |
62.47 % |
Mn |
89.76 % |
Mn2O3 |
|
Hydrogen |
1.15 % |
H |
10.24 % |
H2O |
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Oxygen |
36.39 % |
O |
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|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
Oxides
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Strunz 8th
Ed. ID:
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4/F.06-70
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Nickel-Strunz 10th
Ed. ID:
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4.FD.15
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4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites,
antimonites, bismuthites, sulfites, selenites, tellurites, iodates) F
: Hydroxides (without V or U) D : Hydroxides with OH, without H2O;
chains of edge-sharing octahedra
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Related
to: |
Trimorphous
with Geitknechtite and Groutite
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Varieties: |
None
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Synonyms: |
Grau-Braunsteinerz,
Gray Oxide of
Manganese, Manganaise cristallisé, Manganèse
oxydé metalloïde, Newkirkite, Prismatoidisches
Mangan-Erz, Sphenomanganite
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Crystal
Data
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Crystallography:
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Monoclinic
- Prismatic
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Crystal
Habit:
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Crystals
prismatic and striated || [001], short to long,
to 7.5 cm; typically terminated by {001}, {h0l}, may
be complex. In bundles, subparallel [001], fibrous;
granular, massive.
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Twinning:
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Contact
and penetration twins on {011}; lamellar on {100}.
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Physical
Properties
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Cleavage: |
{010}
Perfect, {110} and {001} Good
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Fracture: |
Irregular/Uneven
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Tenacity:
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Brittle
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Moh's
Hardness: |
4.0
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Density:
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4.29
- 4.34 (g/cm3)
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Luminescence:
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None
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Radioactivity:
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Not
Radioactive
|
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Optical
Properties
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Color: |
Dark
steel-Gray to iron-Black; Red-Brown in transmitted light;
in reflected light, Gray-White with Brownish tint, with
blood-red internal reflections
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Transparency: |
Opaque,
transparent on thin edges
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Luster: |
Sub-metallic
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Refractive
Index: |
2.250
- 2.530 Biaxial ( + )
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Birefringence: |
0.280
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Dispersion: |
Extreme;
r > v
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Pleochroism: |
Weak,
Faint;
X
= reddish brown; Z
= red-brown
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Anisotrophism: |
Weak; Color in reflected light: gray-white
with brown tint; Internal reflections: blood red; Bireflectance:
distinct in grays
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Occurances
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Geological
Setting: |
Formed
in low-temperature hydrothermal or hot-spring manganese
deposits; replacing other manganese minerals in sedimentary
deposits; a component in some clay deposits and laterites.
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Common
Associations: |
Pyrolusite,
Braunite, Hausmannite, Barite, Calcite, Siderite, Goethite
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Common
Impurities: |
Fe,
Ba, Pb, Cu, Al, Ca |
Type
Locality: |
Manganese deposit, Ilfeld,
Nordhausen, Harz Mts, Thuringia, Germany |
Year
Discovered: |
1827
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View
mineral photos: |
Manganite
Mineral Photos and Locations |
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More
Information
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|
|
Mindat.org
Webmineral.com
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Manganite
was at one time a valuable manganese ore. It has been
so heavily mined that it is now somewhat of a rarity
and is considered a minor ore despite its high manganese
content. Fine crystals were once found at Ilfeld,
Harz Mountains and Ilmenau, Thuringia, Germany. Manganite
is opaque black with sub-metallic luster and can be
added to the list of black
gems for collectors.
Manganite
is found at many localities worldwide, but rarely well-crystallized.
Fine crystals from Ilfeld, Harz Mountains, and Ilmenau,
Thuringia, Germany. In the Botallack mine, St. Just,
Cornwall; from Egremont, Cumbria; and at Upton Pyne,
Exeter, Devonshire, England. From Granam, near Towie,
Aberdeenshire, Scotland. At Bölet, near Karlsborg, Västergötland,Sweden.
In the USA, good crystals from the Negaunee and Marquette
districts, Marquette County, Michigan; in the Powell’s
Fort mine, near Woodstock, Shenandoah County, Virginia;
and at Lake Valley, Sierra County, New Mexico. From
the Caland mine, Atikokan, Ontario, Canada. At Kuruman,
Cape Province, South Africa.
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Manganite
gems for sale:
We
have not photographed our Manganite gems. Please
check back soon.
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