Tyrolite

Formula: Ca2Cu9(AsO4)4(CO3)(OH)8 · 11H2O

Species: Arsenates Carbonates

Colour: Turquoise-blue, blue-green; light bluish green in transmitted light.

Lustre: Vitreous, Silky, Pearly

Hardness: 1½ – 2

Specific Gravity: 3 – 3.2

Crystal System: Monoclinic

Name: Named after its discovery locality, Falkenstein near Schwaz, Tyrol, Austria.

Type Locality: Falkenstein, Falkenstein mining district, Schwaz District, Tyrol, Austria

A secondary mineral found in the oxidized zones of copper deposits.

Note: Not all “tyrolites” may contain CO3 groups (see also Church, 1895) and some may be identical with the closely related tangdanite (the ideal formula of which contains no carbonate but sulphate instead). Tyrolite may also be confused with theisite and claraite.