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| Chemistry:
CaMoO4 [Calcium
Molybdenate] | Discovered
in 1891;
IMA
status: Valid (pre-IMA; Grandfathered). Powellite is named after famed American
explorer and geologist, John Wesley Powell (1834 - 1902).
Lake Powell is also named after him. |
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Classification
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Mineral
Classification: |
Molybdates and Wolframates |
Strunz 8th
Ed. ID:
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6/G.01-10 |
Nickel-Strunz 10th
Ed. ID: |
7.GA.05
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7 : SULFATES (selenates, tellurates, chromates, molybdates,
wolframates) G : Molybdates, Wolframates and Niobates A : Without
additional anions or H2O 05:
Powellite - Scheelite series
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Crystal
Data
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Crystallography:
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Tetragonal
- Dipyramidal |
Crystal
Habit:
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Crystals
are usually dipyramidal, less commonly flat tabular
to paper-thin, with many minor forms, to 8 cm; may be
aggregated into crusts, pulverulent, ocherous, massive.
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Twinning:
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None
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Physical
Properties
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Cleavage: |
[112]
Indistinct, [011] Indistinct, [001] Indistinct
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Fracture: |
Uneven
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Tenacity:
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Brittle
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Hardness
(Mohs): |
3.5 - 4.0 |
Density:
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4.26 (g/cm3) |
Luminescence:
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Fluoresces
creamy white or yellow to golden yellow under SW UV. |
Radioactivity:
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Not
Radioactive |
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Optical
Properties
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Color: |
Colorless,
Straw Yellow, Greenish Yellow, Yellowish Brown, Brown;
may be zoned, Blue to nearly Black |
Transparency: |
Transparent,
Translucent |
Luster: |
Sub-Adamantine, Resinous, Pearly |
Refractive
Index: |
1.974 - 1.984 Uniaxial
( + ) |
Birefringence: |
0.011 |
Dispersion: |
0.058
(higher than Diamond) |
Pleochroism: |
In
deeply colored specimens; O
= blue; E
= green
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Occurances
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Geological
Setting: |
An
uncommon secondary mineral, typically formed in the
oxidation zone of molybdenum-bearing hydrothermal mineral
deposits, rarely in basalts, tactites, and granite pegmatites. |
Type
Locality: |
Peacock Mine, Cuprum, Seven Devils District, Adams County, Idaho, USA |
Year
Discovered: |
1891 |
View
mineral photos: |
Powellite
Mineral Photos and Locations |
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More
Information
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|
Mindat.org Webmineral.com |
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Powellite
is a rare member of the Scheelite group of minerals
that also includes Scheelite,
and Wulfenite.
Powellite is
an extremely rare gem, among the rarest of collector's
gems. Prior to a discovery of Powellite crystals
at Pandulena Hill, Nasik District, Maharashtra, India it was unknown as a
gem. Gem quality crystals have since been found in the
Jalgoan District of India as well. The transparent crystals from these locations are very small so gems are
also small. There are several other locations worldwide
where
Powellite is found but none produce gem quality crystals.
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Powellite
gems for sale:
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Gem:
|
Powellite |
Stock
#:
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POW-001 |
Weight:
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0.5135
ct |
Size: |
4.50
x 2.93 mm |
Shape: |
Round |
Color: |
Colorless |
Clarity: |
Eye
clean to VS2 |
Origin: |
Nasik,
India |
Treatment: |
None
(natural) |
Price: |
$153.00
[
Make an offer ] |
Pictures
are of the actual gem offered for
sale. Gem images are magnified to
show detail. |
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|
A
rare and beautiful gem that glows bright yellow
under SW UV. This gem is from Pandulena Hill, Nasik, India.
At over a half carat, this gem is relatively
large for Powellite.
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