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Formula: K2NaMg(SO4)2F
Valence: K2NaMg(S6+O4)2F
Crystal system: Orthorhombic
Specific gravity: 2.498 calculated
Streak: White
Colour: Colourless
Environments
Kantorite is one of the rarest minerals at the Arsenatnaya fumarole. It was approved in 2024 and to date
(December 2025) it has been reported only from the type locality. The temperature measured when it was collected was
about 300°C
(Mindat).
Localities
At the type locality, the Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure
eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia, kantorite was found
associated with aphthitalite,
langbeinite, arcanite,
krasheninnikovite,
vanthoffite, kononovite,
wulffite, halite,
sylvite, flinteite,
fluoborite, chubarovite,
johillerite, urusovite,
zincite, tenorite,
pseudobrookite, hematite,
sanidine and fluorophlogopite.
Kantorite occurs as long-prismatic to acicular crystals up to 0.1 × 0.01 mm which form near-parallel and bush-like
open-work clusters up to 0.2 mm across. It is transparent and colourless with a vitreous lustre.
The structure of kantorite is unique. It represents a quasi-framework in which the basic units are octahedra
[MgO4F2]. They are linked via bridging F atoms to form infinite chains. These chains are encrusted
by [SO4] tetrahedra and assembled into the quasi-framework by alkali cations
(MM 89.5.575-581).
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