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Formula: K6Cu6Tl3+Cl17(OH)4.H2O
Chloride, thallium-bearing mineral
Crystal System: Tetragonal
Specific gravity: 2.95 measured, 2.97 calculated
Hardness: ~3
Streak: White
Colour: Golden yellow to light yellow
Common impurities: Zn
Environments
Chrysothallite was approved in 2013 and to date (August 2023) it has been reported only from the Tolbachik
volcano.
Localities
At the Glavnaya Tenoritovaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption,
Tolbachik volcano, Milkovsky District, Kamchatka Krai, Russia, chrysothallite is associated with
belloite,
avdoninite,
chlorothionite, sanguite,
eriochalcite,
mitscherlichite, sylvite,
carnallite and kainite
(MM 79.365-376).
At the type locality, the Pyatno fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption,
Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia, chrysothallite seems to be a product
of the interactions involving high-temperature sublimate minerals, fumarolic gas and atmospheric water vapour at
temperatures not higher than 150°C. It is associated with belloite,
avdoninite,
chlorothionite,
eriochalcite, atacamite,
halite, kröhnkite,
natrochalcite, gypsum and
antlerite. The chrysothallite forms equant-to-thick tabular
transparent, bright golden-yellow to light yellow crystals up to 0.05 mm, typically combined in clusters or crusts
up to 1 mm across. It forms pseudomorphs after
urusovite
(MM 79.365-376).
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