Goslarite
Goslarite is a hydrated zinc sulfate mineral which was first found in the Rammelsberg mine, Goslar, Harz, Germany. It was described in 1847. Goslarite belongs to the epsomite group which also includes epsomite and morenosite. Goslarite is an unstable mineral at the surface and will dehydrate to other minerals like bianchite, boyleite and gunningite.
Physical properties
The composition of goslarite was determined by the US National Bureau of Standards in 1959 as follows: SO3 27.84 wt%, ZnO 28.30 wt% and 43.86 wt%.Goslarite's cleavage is perfect in, as for epsomite and morenosite. The color of goslarite ranges from brownish to pinkish, blue, brown, colorless, green and green blue. The luster ranges from vitreous to nacreous and silky. Goslarite is soluble in water, has an astringent taste, and is strongly diamagnetic.