Tyrolite
Tyrolite is a hydrated calcium copper arsenate carbonate mineral with formula: CaCu(AsO)CO(OH)·6HO. Tyrolite forms glassy blue to green orthorhombic radial crystals and botryoidal masses. It has a Mohs hardness of 1.5 to 2 and a specific gravity of 3.1 to 3.2. It is translucent with refractive indices of nα=1.694 nβ=1.726 and nγ=1.730. It is a secondary mineral formed by the weathering of associated copper and arsenic minerals. It was first described in 1845 for an occurrence in Schwaz, Tyrol, Austria.