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Powellite
Current inventory:  1 gem
 

Powellite

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.

 

Classification

   

   

Mineral Classification:

Molybdates and Wolframates

Strunz 8th Ed. ID:

6/G.01-10

Nickel-Strunz 10th Ed. ID: 

7.GA.05

 

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
G : Molybdates, Wolframates and Niobates
A : Without additional anions or H
2O
05: Powellite - Scheelite series

Crystal Data

   

   

Crystallography:

Tetragonal - Dipyramidal

Crystal Habit:

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.

Twinning:

None

 

 

Physical Properties

   

 

Cleavage:

[112] Indistinct, [011] Indistinct, [001] Indistinct

Fracture:

Uneven

Tenacity:

Brittle

Hardness (Mohs):

3.5 - 4.0

Density:

4.26 (g/cm3)

Luminescence:

Fluoresces creamy white or yellow to golden yellow under SW UV.

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

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

 

 

Occurances

   

   

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

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


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.
 

  
Powellite gems for sale:

Powellite-001

Gem:

Powellite

Stock #:

POW-001

Weight:

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.

Powellite-001

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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