Sofiite

sofiite

cotunnite

piypite

georgbokiite

Images

Formula: Zn2(Se4+O3)Cl2
Anhydrous selenite
Crystal System: Orthorhombic
Specific gravity: 3.64 calculated
Hardness: 2 to 2½
Streak: White
Colour: Colourless, becoming sky blue on long exposure to air
Solubility: Readily soluble in dilute acids, soluble with difficulty in water
Environments

Fumeroles

Sofiite is a fumarole mineral. On exposure to air it becomes turbid white, and crystals bend and swell; decomposition products form radial aggregates (Mindat).

Localities

At the type locality, the Tolbachik volcano, Kamchatka Krai, Russia, sofiite occurs in fractures in volcanic fumaroles as well-formed, pseudohexagonal thin-platy to micalike crystals associated with cotton-like hygroscopic masses of phases containing zinc and chlorine. Associated minerals include tenorite, cotunnite, piypite, ponomarevite, chalcocyanite, chloromenite, burnsite, ilinskite, georgbokiite, dolerophanite, halite, sylvite and gold. The specimens were collected at temperatures 180 to 230oC (AM 75.1211-1212, HOM).

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