- Aluminite
Aluminite is a hydrous
aluminium sulfate mineral with formula: Al2SO4(OH)4·7(H2O). It is an earthy white to gray-whitemonoclinic mineral which almost never exhibits crystal form. It forms botryoidal to mammillaryclay -like masses. It is very softMohs hardness of 1 with aspecific gravity of 1.66—1.7. It forms as an oxidation product ofpyrite andmarcasite along with aluminous silicates and clays.It was first described in 1807 from Halle, Saxony-Anhalt,
Germany . It is also known as "alley stone" and "websterite" (named after English geologist Thomas Webster).Aluminite is used by tile & masonry workers to reduce the setting time of cementitious mortars.
References
* [http://www.mindat.org/min-154.html Mindat w/ locations]
* [http://webmineral.com/data/Aluminite.shtml Webmineral]
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