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Formula: Ca4.5AlV4+2V5+12O40.28H2O
Vanadate
Specific gravity: 2.8
Hardness: 2
Streak: Pale blue
Colour: Dark bluish black (fresh), blue-green, yellow-green (altered)
Solubility:
Common impurities:
Environments
Sedimentary environments
Hydrothermal environments
Sherwoodite is an oxidation product of lower valent vanadium minerals,
on fracture surfaces and replacing fossil wood in Colorado Plateau-type
sandstone uranium-vanadium
deposits
(Webmin).
Associated minerals include selenium,
metatyuyamunite and
melanovanadite
(HOM).
Localities
At the Ragra mine (Minasragra), Huayllay District, Pasco Province, Pasco, Peru, sherwoodite is associated with
pascoite, pyrite,
copper, gypsum,
patronite and melanovanadite
(HOM).
The type locality is the Peanut mine, Bull Canyon, Uravan Mining District, Montrose County, Colorado, USA.
Sherwoodite is widely distributed in the Uravan mineral belt; localities include the Matchless mine, Mesa
county, Colorado, the Shadyside mine, San Juan county, New Mexico, the Peanut mine, Montrose county, Colorado, and
several other mines. Another locality, the Fall Creek mine, San Miguel County, Colorado, is in the Entrada
sandstone.
Sherwoodite is an oxidation product of lower valent vanadium minerals.
It occurs as coatings on fracture surfaces and along partings in
vanadium-bearing sandstone,
and along fracture surfaces in mineralised coalified wood. It is commonly associated with native
selenium,
metatyuyamunite,
melanovanadite and an undescribed
vanadium mineral resembling
hewettite. It alters to an ill-defined, fine-grained green material,
probably a poorly crystallised compound of quinquivalent vanadium
(AM 43.749-755).
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