Pascoite
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Pascoite is a
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
with formula Ca3V10O28·17H2O that is red-orange to yellow in color. It was discovered in the Pasco Province of Peru, for which it is named, and described in 1914.


Description

Crystals of pascoite, which occur in granular crusts, are minute and lath-like with oblique terminations. The mineral is dark red-orange to yellow-orange in color and dirty yellow when partially dehydrated. It occurs as
efflorescence In chemistry, efflorescence (Derived from the Latin verb 'efflorescere' roughly meaning 'to flower') is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an i ...
s in mine tunnels or as a product leached out of surficial
vanadium oxide Vanadium oxide mainly refers to: * Vanadium(II) oxide (vanadium monoxide), VO * Vanadium(III) oxide (vanadium sesquioxide ''or'' trioxide), V2O3 * Vanadium(IV) oxide (vanadium dioxide), VO2 * Vanadium(V) oxide (vanadium pentoxide), V2O5 Various o ...
s by
ground water Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit of rock or an unconsolidat ...
. Pascoite has been found in association with
carnotite Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula K2( U O2)2( VO4)2·3 H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present. Occurrence Carnotite ...
. Pascoite melts readily to form a deep red liquid. Pascoite is a member of the eponymous pascoite group. The
magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
analogue of pascoite is magnesiopascoite.


Structure

A 2005 study determined that pascoite has a C 2/m disordered
crystal structure In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat ...
. It consists of decavanadate anions (V10O28)6− linked together by the
interstitial {{Short pages monitor