Zykaite or zýkaite is a grey-white mineral consisting of arsenic, hydrogen, iron,

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

and oxygen with formula: Fe³⁺₄(AsO₄)₃(SO₄)(OH)·15(H₂O).Webmineral data
/ref> This dull mineral is very soft with a Mohs hardness of only 2 and a specific gravity of 2.5. It is translucent and crystallizes in the

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

crystal system.Handbook of Mineralogy
/ref> Its common associates include

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

, gypsum,

scorodite Scorodite is a common hydrated iron arsenate mineral, with the chemical formula FeAsO4·2H2O. It is found in hydrothermal deposits and as a secondary mineral in gossans worldwide. Scorodite weathers to limonite. Scorodite was discovered in the S ...

, quartz and arsenopyrite. It is found in the Czech Republic, Poland and Germany. Zykaite was first described in 1978 for an occurrence in the Safary mine, Kutná Hora,

Bohemia Bohemia ( ; cs, Čechy ; ; hsb, Čěska; szl, Czechy) is the westernmost and largest historical region of the Czech Republic. Bohemia can also refer to a wider area consisting of the historical Lands of the Bohemian Crown ruled by the Bohem ...

, Czech Republic and named in honour of Vaclav Zyka (born 1926), a Czech

geochemist Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the ...

.Mindat.org
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References

Sulfate minerals Arsenic minerals Orthorhombic minerals {{Sulfate-mineral-stub