Kieserite, or magnesium sulfate monohydrate, is a hydrousmagnesium sulfate mineral with formula (MgSO4·H2O).
It has a vitreous luster and it is colorless, grayish-white or yellowish. Its hardness is 3.5 and crystallizes in the monocliniccrystal system. Gunningite is the zinc member of the kieserite group of minerals.[5]
Kieserite might also be a rock-forming mineral in the icy mantle of the outer three Galilean moons (Europa, Ganymede, Callisto). At pressures higher than 2.7 GPa, kieserite transforms to a triclinic crystal structure.[6]
Uses
It is used in the production of Epsom salt and as a fertilizer, the overall global annual usage in agriculture in the mid 1970s was 2.3 million tons.[7]
Crystal structure of kieserite
Kieserite is also used for cleaning hard water deposits from tiles, stones, and other pool and fountain lining materials. Due to its hardness, which is greater than hard water deposits but less than tiles and other water feature linings, it is blasted at the hard water deposits to remove them.
When used as a fertilizer, response to kieserite is likely where:
Soil Mg levels are low
pH is high
Intensive liming occurs to raise the pH
Nitrogen is applied as ammonium, as this can lead to an antagonism between ammonium and magnesium
Compacted soils exist
There is a period of wet/cold weather
Dry weather occurs, leading to low magnesium mobility in the soil profile.[8]