Dobrovolskyite

dobrovolskyite

petrovite

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Formula: Na₄Ca(SO₄)₃
Anhydrous sulphate
Crystal System: Trigoal
Specific gravity: 2.68 calculated
Hardness: 3½
Streak: White
Environments

Fumeroles

Dobrovolskyite is a relatively new mineral, approved in 2019 and to date (August 2023) reported only from the type locality.

Localities

At the type locality, the Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik volcano, Kamchatka Krai, Russia, dobrovolskyite occurs as aggregates of tabular crystals up to 2 mm across, with abundant gas inclusions. Dobrovolskyite and similar minerals probably formed upon cooling of a high-temperature phase with disordered cation and anion arrangements (MM 85.2.233-241). It was found in a fumarole, at about 200°C, associated with petrovite (Mindat).

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