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Formula: Cu4O(AsO4)2
Anhydrous arsenate, paramorph of
ericlaxmanite
Crystal System: Orthorhombic
Specific gravity: 4.934 calculated
Hardness: 3½
Streak: Very light green
Colour: Bright grass green to light yellowish green
Environments
Kozyrevskite is a relatively new mineral, approved in 2013 and to date (January 2023) reported only from the
type locality.
Localities
At the type locality, the Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption,
Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia,
ericlaxmanite and kozyrevskite occur in the same mineral
assemblage and are associated intimately with each other; they are also associated closely with the other alkali-free
arsenates urusovite,
lammerite, paralammerite,
popovite and alarsite, and
sometimes with the sodium- or potassium-bearing arsenates
johillerite, bradaczekite,
shchurovskyite and
dmisokolovite. Other associated minerals are
tenorite, hematite,
aphthitalite, langbeinite,
anhydrite, arsenic-bearing
orthoclase, copper-rich
gahnite and, sporadically,
calciolangbeinite, arcanite,
wulffite, krasheninnikovite,
steklite, palmierite
and OH-free fluoborite. All these minerals form complex, polymineralic,
sometimes very rich, incrustations up to 0.5 cm thick on the surface of
basalt scoria in
pockets from 0.3 to 0.8 m deep under the present day surface. The temperature measured inside these pocketsin July 2013
was 360 to 380oC. It is considered that all listed minerals were deposited directly from the gas phase or
were formed as the result of gas-rock interactions at temperatures of not less than 380oC.
Kozyrevskite forms prismatic to long prismatic, typically divergent crystals up to 0.02 x 60.05 x 60.3
mm3 in size and their radiating, sheaf-, bush- or rosette-like clusters up to 0.3 mm across. Abundant
crystals and crystal clusters or, rarely, thin crusts of kozyrevskite occur on incrustations consisting of
langbeinite and arsenic-bearing
orthoclase, or on volcanic
scoria. Kozyrevskite is one of the latest
copper arsenates in the
Arsenatnaya paragenesis, overgrowing not only urusovite and
lammerite but also
ericlaxmanite
(MM 78.1553–1569).
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