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Formula: Zn(SO4).7H2O
Hydrated normal sulphate, epsomite group and forms a series with
epsomite. Epitaxial
mineral: muscovite (Mindat)
Crystal System: Orthorhombic
Specific gravity: 1.978 measured, 1.94 calculated
Hardness: 2 to 2½
Streak: White
Colour: Colourless, white, light brown, green or blue, colourless in transmitted light.
Solubility: Soluble in water, dehydrates in air
Magnetism: Diamagnetic
Environments
Goslarite is a secondary mineral in oxidised portions of
zinc sulphide deposits, particularly as efflorescent crusts on
mine timbers formed from the oxidation of sphalerite (Webmin, Dana, HOM).
Associated minerals include epsomite,
melanterite, pickeringite,
chalcanthite and gypsum
(HOM).
Localities
At the type locality, the Rammelsberg Mine, Rammelsberg, Goslar, Lower Saxony, Germany, goslarite occurs as
efflorescent
crusts on mine timbers formed from the oxidation of sphalerite
(Webmin).
At Creede, Mineral county, Colorado, USA, goslarite is the most common postmining mineral. Silky white growths,
which
can reach a length of over a foot, are commonly found hanging from the backs of drifts in the mines, and are made up of
thousands of hairlike strands
(R&M 85-5.413).
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