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| Tschermakite
was named to honor Professor Gustav Tschermak von Seysenegg
(1836-1927), Austrian mineralogist, University of Vienna,
Vienna, Austria.
| Discovered
in 1945.
IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Ca2Mg3Al3Fe3+Si6O22(OH)2
|
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Calcium
Magnesium Aluminum Iron Silicate Hydroxide |
Molecular
Weight: |
844.38 gm |
Composition: |
Calcium |
9.49 % |
Ca |
13.28 % |
CaO |
|
Magnesium |
8.64 % |
Mg |
14.32 % |
MgO |
|
Aluminum |
9.59 % |
Al |
18.11 % |
Al2O3 |
|
Iron |
6.61 % |
Fe |
9.46 % |
Fe2O3 |
|
Silicon |
19.96 % |
Si |
42.69 % |
SiO2 |
|
Hydrogen |
0.24 % |
H |
2.13 % |
H2O |
|
Oxygen |
45.48 % |
O |
|
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|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
Silicates
(Germanates)
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Strunz 8th
Ed. ID:
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8/F.10-60
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Nickel-Strunz 10th
Ed. ID:
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9.DE.10
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9 : SILICATES (Germanates)
D : Inosilicates E : Inosilicates with 2-periodic double chains, Si4O11; Clinoamphiboles
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Related
to: |
Amphibole
Group. Calcic Clino-Amphibole Subgroup. Tschermakite
- Ferrotschermakite Series.
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Synonyms: |
Tschermakitic
hornblende, Aluminotschermakite
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Crystal
Data
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Crystallography:
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Monoclinic
- Prismatic
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Crystal
Habit:
|
As
prismatic crystals; as reaction rims on other minerals.
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Twinning:
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Simple
or multiple twinning || {100}.
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Physical
Properties
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Cleavage: |
Perfect
on {110}, intersecting at 56º and 124º; partings on
{100}, {001}.
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Fracture: |
Conchoidal
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Tenacity:
|
Brittle
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Moh's
Hardness: |
5.0
- 6.0
|
Density:
|
3.15 (g/cm3)
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Luminescence:
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None |
Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Medium Green to dark Green to Green-Black to Black, Brown (rare).
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Transparency: |
Transparent
to Opaque
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Luster: |
Vitreous
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Refractive
Index: |
1.68
- 1.698 Biaxial ( + ) or ( - )
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Birefringence: |
0.0180
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Dispersion: |
Strong;
r > v
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Pleochroism: |
Visible
to Distinct; in greens and browns
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Occurances
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Geological
Setting: |
From
eclogites and other ultramafic igneous rocks, and in
medium- to high-grade metamorphic rocks, typically amphibolites.
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Common
Associations: |
Kyanite,
Garnet |
Common
Impurities: |
Ti,
Mn, Na, K, H2O
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Type
Locality: |
(possibly
Bamle, Norway) |
Year
Discovered: |
1945
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View
mineral photos: |
Tschermakite
Mineral Photos and Locations |
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More
Information
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|
Mindat.org
Webmineral.com
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Tschermakite
is a fairly common but rarely identified mineral. It
often occurs in association with massive green Zoisite
and Ruby at the Mundarara Mine, Longido,
Mt. Kilimanjaro, Kilimanjaro Region of Tanzania. Black
inclusions of Tschermakite are frequently seen in attractive
cabochons of bright green Zoisite and pinkish-red Ruby.
Probably
widespread. Well-studied material from: Hurry Inlet,
Fiskenæsset, Greenland. At Glenelg and Knockormal, Ayrshire,
Scotland. From Lake Kutemajärvi, Orivesi, and Perniö,
Finland. In France, from Le Viala du Tarn, Aveyron.
From the central Bug region, Ukraine.
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Tschermakite
gems for sale:
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