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| Tremolite
was named by J.G.A. Höpfner for the Tremola valley (Val Tremola), Central St
Gotthard Massif, Switzerland, where the type material supposedly came from,
according to the dealer from whom he had acquired the specimens. See more name
information below.
| Discovered
in 1790; IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Ca2(Mg;Fe2+)5Si8O22(OH)2
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Calcium Magnesium Iron
Silicate Hydroxide |
Molecular
Weight: |
812.37 gm
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Composition: |
Calcium |
9.87 % |
Ca |
13.81 % |
CaO |
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Magnesium |
14.96 % |
Mg |
24.81 % |
MgO |
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Silicon |
27.66 % |
Si |
59.17 % |
SiO2 |
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Hydrogen |
0.25 % |
H |
2.22 % |
H2O |
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Oxygen |
47.27 % |
O |
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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.10-10
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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. Calcic
Clino-Amphibole Subgroup. Tremolite - Sadanagaite Series.
Tremolite - Parvo-manganotremolite Series. Actinolite
- Tremolite Series. Ferro-Actinolite - Tremolite Series.
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Members
of Supergroup: |
Amphibole Supergroup:
Lithium Amphibole Subgroup,
Lithium - (Magnesium - Iron - Manganese) Amphibole Subgroup,
Lithium-Calcium Amphibole Subgroup, Magnesium - iron
- manganese Amphibole Subgroup, Sodium Amphibole Subgroup,
Sodium - (Magnesium - Iron - Manganese) Amphibole Subgroup,
Sodium-Calcium Amphibole Subgroup
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Varieties: |
Chrome-Tremolite,
Hexagonite
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Synonyms: |
Abhazite,
Abkhazite, Calamite, Grammatite, Peponite, Raphilite,
Säulenspath, Sebesite, Sternspath
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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, or flattened bladed crystals, to 20
cm; also fibrous, granular or columnar aggregates.
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Twinning:
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Simple
or multiple, common || {100}; rarely multiple || {001}
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Physical
Properties
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Cleavage: |
Perfect
on [110]; partings on [010], [100]
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Fracture: |
Sub-Conchoidal
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Tenacity:
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Brittle
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Moh's
Hardness: |
5.0
- 6.0
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Density:
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2.99
- 3.03 (g/cm3)
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Luminescence:
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Fluorescent; SW UV
= yellow, LW UV = pink |
Radioactivity:
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Not
Radioactive
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Health
Warning: |
Asbestiform varieties of Tremolite can cause lung disease when inhaled, as with other species of asbestos minerals.
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Optical
Properties
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Color: |
White,
Brown, Gray, Colorless, light to dark Green, light Yellow,
Pink to Violet; colorless in thin section
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Transparency: |
Transparent
to Translucent, Opaque
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Luster: |
Vitreous,
Silky
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Refractive
Index: |
1.599
- 1.637 Biaxial ( - )
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Birefringence: |
0.0250
- 0.0260
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Dispersion: |
Weak;
r < v
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Pleochroism: |
None
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Occurances
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Geological
Setting: |
From
contact metamorphism of Ca-Mg siliceous sediments; in
greenschist facies metamorphics derived from ultramafic
or magnesium carbonate rocks. |
Common
Associations: |
Calcian
Garnet, Calcite, Cummingtonite, Diopside, Dolomite,
Forsterite, Magnesio-cummingtonite, Riebeckite, Talc,
Winchite, Wollastonite |
Common
Impurities: |
Ti,
Mn, Al, Na, K, F, Cl, H2O
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Type
Locality: |
Campolungo, Piumogna Valley, Leventina, Ticino (Tessin), Switzerland
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Year
Discovered: |
1790
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View
mineral photos: |
Tremolite
Mineral Photos and Locations |
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More
Information
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Mindat.org
Webmineral.com
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Tremolite
is a relatively common mineral but rare as a faceted
gem. Most mineral specimens are fibrous, granular or columnar aggregates
and not suitable for faceting. The crystals that are
transparent, clean and brightly colored are very rare.
Tremolite is a member of the Calcic Clino-Amphibole Subgroup
of the Amphibole Group of minerals that includes Actinolite,
Ferro-edenite, Kaersutite,
Pargasite,
Richterite and
Tremolite.
The Amphibole Group is an extensive and complex group
of minerals currently divided into several sub-groups.
Gem quality Tremolite gets its vivid green coloring
from the iron (Fe) content. A pale lilac to purplish
color variety of Tremolite is called Hexagonite
and is colored by manganese (Mn).
A green chromium (Cr) rich variety called Chrome
Tremolite
is found
mainly in the Merelani Hills
of Tanzania.
Tremolite
was named by J.G.A. Höpfner for the Tremola valley (Val Tremola), Central St
Gotthard Massif, Switzerland, where the type material supposedly came from,
according to the dealer from whom he had acquired the specimens. Though, modern
investigations of what is considered the type material, conserved at Geneva,
revealed that the type locality is actually Campolungo. Val Tremola lying north of the
isograde delineating the first appearance of Tremolite.
The
only notable sources of gem quality crystals of Tremolite
are Harcourt, Haliburton County, Ontario, Canada; Outokumpu, Itä-Suomen Lääni, Finland;
Umba Valley region, Kenya; Northern Areas,
Astor District Astor,
Pakistan; Merelani Hills (Mererani), Lelatema Mts, Simanjiro District, Manyara Region, Tanzania.
In the
USA, from Pierrepont, Gouverneur, Edwards, and Macomb,
St. Lawrence County, New York; at Franklin, Sussex County,
New Jersey; and Lee, Berkshire County, Massachusetts.
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Tremolite
gems for sale:
We
have not photographed our Tremolite gems. Please
check back soon.
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