Bohuslavite

bohuslavite

gypsum

albite

pyrite

Images

Formula: Fe3+4(PO4)3(SO4)(OH)(H2O)10.nH2O (5 ≤ n ≤ 14)
Phosphate
Specific gravity: 2.05 to 2.09
Hardness: 3
Streak: White
Colour: Colourless to pinkish to lilac under incandescent light, white to yellowish under sunlight
Luminescence: Not fluorescent under UV
Solubility: Very slowly soluble in concentrated hydrochloric acid at room temperature
Environments

Volcanic igneous environments
Metamorphic environments

Bohuslavite is a relatively new mineral, approved in 2019.

Localities

There are two co-type localities, Horní Město, Bruntál District, Moravian-Silesian Region, Czech Republic, and Buca della Vena Mine, Pontestazzemese, Stazzema, Lucca Province, Tuscany, Italy.
The Buca della Vena mine exploited a small baryte-pyrite-iron oxide ore deposit.
The Horní Město ore deposit is an example of metamorphosed iron-zinc-lead-(silver) sulphide mineralisation in volcano-sedimentary rocks.
At the Buca della Vena mine, bohuslavite is associated with gypsum in fractures of pyrite-rich phyllite. Rarely, it has also been observed in vugs of quartz-albite veins, associated with pyrite.
A similar mineral association has been observed at the Horní Město ore deposit, where bohuslavite was rarely found in fissures of quartz–carbonate veins, in association with abundant white to colourless gypsum.
It seems likely that at these localities the genesis of bohuslavite is related to the action of sulphuric acid generated by the pyrite oxidation on phosphate-bearing phases such as apatite.
At both occurrences, bohuslavite occurs as tabular crystals with pseudohexagonal outline, up to 250 microns in size, forming globular aggregates up to 1 mm across. The mineral is colourless to pinkish to lilac under incandescent light; under sunlight, it is white to yellowish (EJM 31.1033-1046).

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