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Formula: KZn(AsO4)
Arsenate
Crystal System: Hexagonal
Specific gravity: 4.748 calculated for the empirical formula
Colour: Colourless in separate crystals to white in aggregates; some samples are green due to abundant micro-inclusions
of copper-rich arsenates, mainly
shchurovskyite.
Luminescence: Non-fluorescent under UV or an electron beam
Environments
Pharmazincite is a relatively new mineral, approved in 2017 and to date (January 2024) 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, specimens with pharmazincite were
collected from the inner, hot part of the fumarole, at a temperature of 360 to 380°C. It is suggested that
pharmazincite was deposited directly from the gas phase as a volcanic sublimate at temperatures higher than
360°C. It is a minor constituent of fumarolic incrustations also including
shchurovskyite,
dmisokolovite, bradaczekite,
arsmirandite, tilasite,
johillerite, lammerite,
paralammerite, urusovite,
alarsite, ericlaxmanite,
kozyrevskite, popovite,
svabite, melanarsite,
hatertite, yurmarinite,
aphthitalite, langbeinite,
calciolangbeinite,
krasheninnikovite, arcanite,
palmierite, steklite,
dolerophanite, anhydrite,
alumoklyuchevskite,
vanthoffite, fluoborite,
sylvite, halite,
hematite, tenorite,
copper-bearing gahnite,
corundum, orthoclase and
fluorophlogopite.
Pharmazincite occurs as prismatic to acicular crystals up to 1 mm long and up to 0.03 mm thick typically
combined in nearparallel, radial or chaotic intergrowths, open-work aggregates or crusts up to 2 mm across. It is one
of the latest minerals in the assemblage; its crystals and aggregates occur on crusts formed by other
arsenates, mainly
shchurovskyite,
dmisokolovite, tilasite,
bradaczekite, arsmirandite
and tilasite pseudomorphs after
johillerite crystals. These polycomponent arsenate incrustations cover,
along with tenorite and later
aphthitalite, basalt
scoria altered by fumarolic gas. Areas ‘sprinkled’ by
pharmazincite clusters are up to 1 cm × 2 cm
(MM 81.4.1001-1008).
Pharmazincite from the Arsenatnaya Fumerole -
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