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Aluminite



Aluminite is a hydrous aluminium sulfate mineral with formula: Al2SO4(OH)4·7(H2O). It is an earthy white to gray-white monoclinic mineral which almost never exhibits crystal form. It forms botryoidal to mammillary clay-like masses. It is very soft Mohs hardness of 1 with a specific gravity of 1.66—1.7. It forms as an oxidation product of pyrite and marcasite along with aluminous silicates and clays.

Additional recommended knowledge

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

  • Mindat w/ locations
  • Webmineral
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Aluminite". A list of authors is available in Wikipedia.
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