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CyanotrichiteCyanotrichite is a copper aluminium sulfate mineral with formula Cu4Al2[(OH)12|SO4]·2H2O, also known as lettsomite, very similar to halotrichite, and a member of the same group. It forms velvety aggregates of extremely fine fibres and radial aggregates. It crystallizes in the orthorhombic system and forms translucent bright blue acicular crystal clusters or drusey coatings. The Mohs hardness is 2 and the specific gravity ranges from 2.74 to 2.95. Refractive indices are nα=1.588 nβ=1.617 nγ=1.655. It is an oxidation product of primary copper mineralization in a weathering environment with abundant Aluminium and sulfate. The main deposits are Cap la Garrone in the Var (France), Romania and Arizona (USA). (source: Wikipedia) Return to List Back to Michael's Hobbies page Back to Michael Marcotte's HomePage