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Formula: KZnCl3.2H2O
Valence: KZn2+Cl3.2H2O
Hydrated chloride of potassium and zinc; The mineral name is based on two Greek
words, κρύος, cold or ice, and βóστρυξ, curl, reflecting the typical appearance: visually, anthodites (cave formations
composed of long needle-like crystals situated in clusters which radiate outward from a common base) of the mineral are
very similar to ice curls.
Crystal System: Monoclinic
Specific gravity: 2.30 measured, 2.300 calculated
Hardness: 2
Streak: White
Colour: Colourless
Solubility: Readily dissolves in water at room temperature
Common impurities: Tl
Environments
Cryobostryxite was approved in 2014 and to date (July 2026) ir has been reported only from the type locality.
Localities
At the type locality, the Northern fumarole field, First scoria cone, Northern Breakthrough, Great Fissure eruption,
Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia, cryobostryxite occurs as a
secondary mineral formed in the upper, moderately hot (30 to 80°C)
zone of active fumaroles, probably as a product of the interactions between high-temperature volcanic sublimates and
meteoric water. It is associated with gypsum,
hydrokenoralstonite and opal;
earlier,
primary minerals of the assemblage are
sellaite, fluorite,
halite, anhydrite,
cotunnite, sofiite,
flinteite, chubarovite,
anglesite, challacolloite,
zincomenite, saltonseaite,
hollandite, hematite,
leonardsenite
and olsacherite.
Cryobostryxite occurs as anthodites (cave formations composed of long needle-like crystals situated in clusters
which radiate outward from a common base) (up to 0.5 × 2 mm), their aggregates (up to 4 × 5 mm), granular crusts
(up to 2 × 2 mm) and, rarely, coarse prismatic to acicular crystals (up to 0.2 × 1 mm). The mineral is transparent and
colourless, with a vitreous lustre
(EJM 27.6.805-812)
Cryobostryxite from the Northern fumarole field -
Image
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