Alunite group

Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite. left|thumb|Alunite from Slovakia Alunite crystals morphologically are rhombohedra with interfacial angles of 90° 50', causing them to resemble cubes. Crystal symmetry is trigonal. Minute glistening crystals have also been found loose in cavities in altered rhyolite. Al

Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct during the purification and refining of zinc and is also commonly associated with acid mine drainage and acid sulfate soil environments.

Osarizawaite is a greenish yellow sulfate mineral with the chemical formula: PbCuAl2(SO4)2(OH)6. It has rhombohedral crystals.

Argentojarosite is an iron sulfate mineral with the chemical formula AgFe(SO)(OH). It is one of few iron sulfate minerals containing silver in its chemical formula as a dominant element. Its type locality is the East Tintic Mountains, Utah.