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| Chemistry:
Ca2Mg5(Si8O22)(OH)2 | Discovered
in 1789 (Tremolite);
IMA
status: Hexagonite: Not Valid; Tremolite: Valid Hexagonite was
named for being a hexagonal form of Tremolite but
was later shown to be monoclinic. The name Hexagonite
has been rejected by the IMA. Tremolite
was named by J.G.A. Höpfner for
the Tremola Valley (Val Tremola), Central St. Gotthard
Massif, Switzerland where the type material was originally
thought to be found. |
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Classification
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Mineral
Classification: |
Silicates |
Strunz 8th
Ed. ID:
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8/F.10-10
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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; Forms a series with Actinolite; Forms a series with Ferro-Actinolite; Forms a series with Parvo-manganotremolite
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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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Elongated, stout prismatic, bladed crystals, fibrous, granula, columnar
aggregates
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Twinning:
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Tremolite:
Simple or multiple: common parallel to [100], rarely parallel to [001]
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Physical
Properties
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Cleavage: |
[110]
Perfect
, [010] Distinct
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Fracture: |
Uneven
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Tenacity:
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Brittle
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Hardness
(Mohs): |
5.0 - 6.0
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Density:
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2.90
- 3.20 (g/cm3)
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Luminescence:
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Orange,
medium pink to pinkish red fluorescence in LW and SW
UV |
Radioactivity:
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Not
Radioactive |
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Optical
Properties
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Color: |
Pale Lilac, deep Rose,
deep Red-Violet, Purplish
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Transparency: |
Transparent,
Translucent |
Luster: |
Vitreous |
Refractive
Index: |
1.599
- 1.637 Biaxial ( - )
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Birefringence: |
0.019 - 0.028
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Dispersion: |
Weak;
r < v |
Pleochroism: |
Bluish-Red/deep
Rose/deep Red-Violet
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Occurances
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Geological
Setting: |
Contact metamorphism of Ca-Mg siliceous sediments, regional greenschist
metamorphism of ultramafic rocks or magnesium carbonate rocks. |
Common
Associations: |
Calcite,
Dolomite, Calcian Garnet, Wollastonite, Talc, Diopside,
Forsterite, Cummingtonite, Magnesio-Cummingtonite, Riebeckite,
Winchite
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Type
Locality: |
Edwards, Balmat-Edwards Zinc District, St Lawrence County, New York, USA |
Year
Discovered: |
1789
(Tremolite)
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View
mineral photos: |
Hexagonite
Mineral Photos and Locations |
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More
Information
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Mindat.org
(Hexagonite) Mindat.org
(Tremolite) Webmineral.com
(Tremolite)
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Hexagonite is the
rarest of the gem varieties of Tremolite. It is the
Manganoan variety of Tremolite distinguished by its
pale lilac to purplish color. Tremolite is a member
of the Amphibol mineral group that also includes Actinolite,
Jade and Nephrite.
Hexagonite is found only in New York, USA
in four locations: Edwards, Fowler and Talcville
in St. Lawrence County; and Harrisville in Lewis
County.
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Hexagonite
gems for sale:
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Gem:
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Hexagonite |
Stock
#:
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HEX-001 |
Weight:
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0.1460
ct |
Size: |
4.16
x 3.04
x 1.83 mm |
Shape: |
Oval |
Color: |
Pink |
Clarity: |
SI2
- I2 |
Origin: |
Edwards,
New York, USA |
Treatment: |
None
(natural) |
Price: |
SOLD
(but we have others) |
Pictures
are of the actual gem offered for
sale. Gem images are magnified to
show detail. |
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A
very rare collector's gem from Edwards,
New York, USA.
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