Dioptase (on calcite)

calcite

An iron-stained carbonate matrix encrusted with coarse, sparry calcite including free-standing rhombs (to 35 mm). The latter are directionally coated with saccharoidal, iron oxide stained calcite and small (< 1 mm) dioptase crystals.
The specimen was number 140 in the collection of Clement Victor Latz, which was donated to the Australian Bureau of Mineral Resources (now Geoscience Australia) in 1976. There is no record of earlier provenance but the paragenesis and vintage of the specimen are diagnostic for the second oxidation zone.