Dioptase (w. cerussite)

calcite; cerussite; conichalcite-duftite

A siliceous matrix encrusted with conichalcite-duftite (not analysed) and colourless to very slightly pink sub-mm rhombohedral calcite crystals. These are in turn sparsely peppered with gemmy dioptase crystals (to 16 mm) and colourless cerussite (to 15 mm). The dioptase appears to post-date the cerussite. A little plancheite is associated on the reverse side of the specimen.

The specimen was donated to the Australian Bureau of Mineral Resources (now Geoscience Australia) by C. M. Chidley in 1975. There is no record of earlier provenance or location in the mine, but the paragenesis is diagnostic for the second oxidation zone.