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Formula: Cu4Fe3+O2(V2O7)(VO4)
Vanadate
Crystal System: Orthorhombic
Specific gravity: 4.10 calculated
Streak: Dark brown-red
Colour: Iron-black to reddish black
Environments
Kainoptrite is a relatively new mineral, approved in 2015, and to date reported only from the Tolbachik volcano.
Localities
The type locality is the Yadovitaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption,
Tolbachik volcano, Kamchatka Krai, Russia. Kainotropite is one of the rarest minerals in the Tolbachik fumaroles.
It was discovered in a single specimen collected from the Yadovitaya fumarole. It is thought that it was deposited
directly from hot gases as a volcanic sublimate, at temperatures not lower than 300oC.
In the holotype specimen, kainotropite forms well-shaped prismatic crystals up to 0.04 × 0.05 × 0.2 mm in size,
which are slightly divergent and combined in clusters up to 0.1 × 0.25 mm. They occur on a
langbeinite crust overgrowing
basalt scoria.
Kainotropite is intimately associated with hematite,
tenorite, piypite, and a
potassium-sodium-lead chlorosulfate. Other associated minerals are lyonsite,
rutile, pseudobrookite,
arsenic-bearing sanidine,
calciolangbeinite and
lammerite
(CM 58.2.155-165).
At the Southern fumarole field, Mountain 1004, Tolbachik volcano, Kamchatka Krai, Russia, kainotropite was
detected in a specimen collected from the fumarolic deposits. Kainotropite occurs here as prismatic crystals up
to 0.2 × 0.2 × 0.5 mm in size, isolated or combined in clusters up to 0.7 mm across. The crystals overgrow volcanic
scoria strongly altered by fumarolic gas. Kainotropite is
associated here with diopside and
hematite; supergene
minerals observed in this specimen are volborthite,
brochantite, gypsum and
opal
(CM 58.2.155-165).
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