157 rock samples taken from the Samin Ltd open cut copper mine at Burra were investigated by Amdel to determine their metallic elemental content, and petrological and mineragraphic features that might be diagnostic of rock and mineral genesis. Host rock groups of both sedimentary and volcaniclastic origin were noted, these having characteristic microscopic structures (e.g. veined, vesicular and perlitic textures) and complex composition showing evidence of subsequent hydrothermal alteration and extensive feldspathisation, with clast or phenocryst minerals frequently replaced by other, secondary species as pseudomorphs. The principal ore minerals are finely crystalline malachite and azurite, with lesser chalcocite and covellite, often silicified and partly replacing cuprite blebs, or exhibiting complete replacement textures after ?chalcopyrite or occasionally, sphalerite or bornite. Recommendations are given for further work needed to establish the paragenesis of alteration-stage dolomite and calcite phases, and to more completely understand the processes and history of potassium and magnesium metasomatism of what appear largely to have been fine-grained volcanogenic original country rocks. The undoubted role in copper mineralisation played by local shears and fault zones may also be further elucidated by studying the subtle records of tectonism also seen preserved in the rocks.