Tyrolite, Tangdanite, Erythrite and Azurite

A highly brecciated specimen interwoven with fracture and pore-filled copper and cobalt mineralisation.  The specimen contains Tyrolite, Tangdanite, Erythrite and Azurite and is from the Geyer-Silberberg District in the Brixlegg-Schwaz Area of North Tyrol, Austria.  The mineral Tangdanite was formerly named Clinotyrolite.  The Azurite and Erythite are readily identified in the specimen, being their characteristic blue and cobalt-pink.  The distinction between Tyrolite and Tangdanite is very difficult however, as they are both greenish-blue with a somewhat radial, fibrous structure.  Tyrolite is a hydrated calcium copper arsenate carbonate whereas Tangdanite is essentially Tyrolite with sulphate rather than carbonate.  Both species are present although not individually discernible.  Nonetheless, a terrific specimen.