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| Potassic-fluoro-hastingsite
(Fluoro-potassic-hastingsite)
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Discovered
in 2005;
IMA
status:
Valid (IMA approved
2005)
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Chemistry
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Chemical
Formula: |
KCa2(Fe42+Fe3+)(Al2Si6O22)(F,OH)2
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Potassium
Calcium Iron Aluminum Silicate Floride Hydroxide |
Molecular
Weight: |
947.86 gm
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Composition: |
Potassium |
4.12 % |
K |
4.97 % |
K2O |
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Calcium |
8.46 % |
Ca |
11.83 % |
CaO |
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Magnesium |
5.13 % |
Mg |
8.50 % |
MgO |
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Aluminum |
5.69 % |
Al |
10.76 % |
Al2O3 |
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Iron |
17.68 % |
Fe |
15.16 % |
FeO
/ 8.42 % Fe2O3 |
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Silicon |
17.78 % |
Si |
38.03 % |
SiO2 |
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Oxygen |
37.13 % |
O |
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Fluorine |
4.01 % |
F |
4.01 % |
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-
% |
F |
-1.69 % |
-O=F2
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100.00 % |
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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.10-145
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Nickel-Strunz 10th
Ed. ID:
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9.DE.15
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9 : SILICATES (Germanates) D : Inosilicates E : Inosilicates with 2-periodic double chains, Si4O11; Clinoamphiboles
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Related
to: |
Hastingsite Root Name Group.
Calcium Amphibole Subgroup.
w(OH, F, Cl)-dominant Amphibole Group.
Amphibole Supergroup.
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Members
of Group: |
Hastingsite Root Name Group:
Fluoro-hastingsite, Hastingsite, Magnesio-fluoro-hastingsite,
Magnesio-hastingsite, Potassic-chloro-hastingsite, Potassic-fluoro-hastingsite,
Potassic-hastingsite, Potassic-magnesio-hastingsite
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Members
of Sub-Group: |
Calcium
Amphibole Subgroup:
Cannilloite Root Name,
Edenite Root Name, Hastingsite Root Name, Hornblend
Root Name, Pargasite Root Name, Sadanagaite Root Name,
Tremolite-Actinolite Series, Tschermakite Root Name
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Varieties: |
None
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Synonyms: |
IMA2005-006,
Fluoro-potassic-hastingsite
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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; in compact aggregates to 1 cm
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Twinning:
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None
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Physical
Properties
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Cleavage: |
Perfect
on {110}, intersecting at 56°
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Fracture: |
Concoidal,
sub-concoidal
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Tenacity:
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Brittle
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Moh's
Hardness: |
6.0
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Density:
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3.289 (g/cm3)
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Luminescence:
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None
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Radioactivity:
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Barely
Detectable;
GRapi = 58.40 (Gamma Ray American Petroleum Institute Units)
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Optical
Properties
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Color: |
Black,
dark greenish black on thin edges
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Transparency: |
Transparent to
translucent
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Luster: |
Vitreous,
sub-vitreous
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Refractive
Index: |
1.668
- 1.698 Biaxial ( - )
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Birefringence: |
0.030
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Dispersion: |
Moderate
to strong; r
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Pleochroism: |
Strong;
X
= bluish green; Y
= greenish to brownish green; Z
= blue to light blue
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Occurances
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Geological
Setting: |
A
product of potassium-halogen metasomatism of a hastingsite
and diopside-bearing rock. A magnetite-rich iron ore deposit hosted by Proterozoic metamorphic rocks.
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Common
Associations: |
Magnetite,
Diopside, Enstatite, Pyrrhotite, Chalcopyrite, Pyrite,
Phlogopite |
Common
Impurities: |
Na,
Mg, Cl |
Type
Locality: |
Greenwood mine (Patterson mine), Town of Tuxedo, Orange County, New York, USA
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Year
Discovered: |
2005;
IMA
approved 2005, IMA redefined and renamed 2012 |
View
mineral photos: |
Potassic-fluoro-hastingsite
Mineral Photos and Locations |
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Unusual
Gem Categories
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Black
Gems |
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More
Information
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Mindat.org Webmineral.com
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Potassic-fluoro-hastingsite
is a rare member of the Calcium Amphibole Subgroup of
minerals that also includes Actinolite,
Pargasite,
Sadanagaite,
Tremolite and
Tschermakite.
Potassic-fluoro-hastingsite
is very rare and
obscure mineral and only found in one place in the world - the Greenwood
Mine in the Town of Tuxedo, Orange County, New York, USA. It is rarely found
in mineral collections and even rarer as a faceted gem!
It is black with vitreous luster and is barely
radioactive due to its potassium content.
Potassic-fluoro-hastingsite
was discovered in 2005 in the tailings dump of
the Greenwood (Patterson) iron mine. The mine, located
in Hudson Highlands, in Harriman State Park, Town of
Tuxedo, Orange County, New York, USA, was first opened in
1838, and was a source of iron during the Civil War.
It was last worked in 1880.
This
mineral was originally named Fluoro-potassic-hastingsite
in 2009 by Marian V. Lupulescu, John Rakovan, M. Darby Dyer, George
W. Robinson, and John M. Hughes for its chemical relationship to
Hastingsite. But it was redefined and renamed in 2012 by the Amphibole
Subcomittee of the Commission on New Minerals, Nomenclature and Classification (CNMNC).
The new IMA approved name is Potassic-fluoro-hastingsite
following the principle that the various
prefixes to the root name are listed in the order they occur in the formula.
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