Fluoro-potassichastingsite
Current inventory:  0 gems
 

  
Fluoro-potassichastingsite is named for its Fluorine and Potassium content and its relationship to Hastingsite. Hastingsite is named for the locality in Dungannon Township, Hastings County, Ontario, Canada where it was discovered.

Discovered in 2005;   IMA status:  Valid (IMA approved 2005)

Chemistry

Chemical Formula:

[K][Ca₂][Fe²⁺₄Mg₂Fe³⁺][(F₂OH)Al₂Si₆O₂₂]

Potassium Calcium Iron Aluminum Silicate Hydroxide Floride

Molecular Weight:

947.86 gm

Composition:

Potassium

4.12 %

K

4.97 %

K₂O

Calcium

8.46 %

Ca

11.83 %

CaO

Magnesium

5.13 %

Mg

8.50 %

MgO

Aluminum

5.69 %

Al

10.76 %

Al₂O₃

Iron

17.68 %

Fe

15.16 %

FeO / 8.42 % Fe₂O₃

Silicon

17.78 %

Si

38.03 %

SiO₂

Oxygen

37.13 %

O

Fluorine

4.01 %

F

4.01 % 

  -  %

F

-1.69 %

 -O=F₂

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/F.10-145

Nickel-Strunz 10th Ed. ID:

9.DE.15

9 : SILICATES (Germanates)
D : Inosilicates
E : Inosilicates with 2-periodic double chains, Si₄O₁₁; Clinoamphiboles

Related to:

Amphibole Group. Calcic Clino-Amphibole Subgroup.

Varieties:

None

Synonyms:

IMA2005-006

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Prismatic crystals, to 4 cm.

Twinning:

May have simple or multiple twinning common || {100}.

Physical Properties

Cleavage:

Perfect on {110}

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

5.0 - 6.0

Density:

3.35 - 3.50 (g/cm³)

Luminescence:

None

Radioactivity:

Barely Detectable; GRapi = 58.40 (Gamma Ray American Petroleum Institute Units)

Optical Properties

Color:

Black

Transparency:

Opaque to Semi-Transparent in very thin pieces

Luster:

Vitreous

Refractive Index:

1.669 - 1.705  Biaxial  ( - ) (information derived from Hastingsite)

Birefringence:

0.0150 - 0.0250 (information derived from Hastingsite)

Dispersion:

Moderate to Strong; r < v

Pleochroism:

None

Occurances

Geological Setting:

An iron mine in magnetite ore. Host rock is hornblende gneiss.

Common Associations:

Albite-Anorthite, Biotite, Chalcopyrite, Diopside, Enstatite, Fluorapatite, Magnetite, Molybdenite, Phlogopite, Pyrite, Pyrrhotite, Quartz, Zircon

Common Impurities:

Na, Mg, Cl

Type Locality:

Greenwood mine (Patterson mine), Town of Tuxedo, Orange Co., New York, USA

Year Discovered:

IMA approved

View mineral photos:

Fluoro-potassichastingsite Mineral Photos and Locations

More Information

Mindat.org 
Webmineral.com

Fluoro-potassichastingsite is very rare and obscure mineral and only found in one mine in the entire world - the Greenwood Mine in Orange County, New York (Hudson Highlands region). It is rarely found in mineral collections and even rarer as a faceted gem! It is opaque black with vitreous luster is very barely radioactive due to its potassium content.
 

  
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