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Formula: Mn2+V5+2O6.4H2O
Vanadate of manganese
Crystal System: Monoclinic
Specific gravity: 2.5 to 2.55 measured, 2.49 calculated
Hardness: 3
Streak: Orange
Colour: carmine red to wine red
Luminescence: No fluorescence under UV
Solubility: Unstable in air and aqueous solutions at temperatures above about 50 to 85oC (Webmin).
Environments
Sedimentary environments
Metamorphic environments
Localities
At the type locality, Fianel, Ausserferrera, Ferrera, Viamala Region, Grisons, Switzerland, ansermetite occurs
sparingly at the iron-manganese
deposit that
is of synsedimentary to diagenetic origin, embedded in carbonates. It underwent a polyphase metamorphism, climaxing at
conditions of the blueschist to
greenschist facies. The following three stages of
vanadate crystallisation have been recognized at Fianel:
(1) medaite crystallises along the main
greenschist facies schistosity
(2) palenzonaite, saneroite
and minor
quantities of pyrobelonite occur in veinlets filled with massive
quartz, aegirine and
rhodonite that crosscut the main schistosity
(3) fianelite, ansermetite and
iron
oxyhydroxides occur in thin fractures near or across the
palenzonaite-bearing
veinlets. Fianelite and ansermetite represent the latest stage in the
remobilisation of vanadium.
Ansermetite fills thin open fractures. Crusts reach a thickness of up to about 500 microns and can cover several
square centimetres. Rare individual crystals can reach 100 microns in size
(CM 41.1423-1431).
At the Packrat Mine, Beaver Mesa, Gateway Mining District, Mesa county, Colorado, USA, ansermetite is
associated with
kegginite, gypsum,
mesaite and sherwoodite
(AM 102.2.461–465).
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