The analysis of a series of Aboriginal breastplates in the collections of the National Museum of Australia has illustrated the development of early metallurgical processes and the effective reworking of shipwreck fittings into functional objects. The presence of minor alloying constituents has a major impact on the formation of the zinc-rich [beta]?phase of brasses which can confer better physical properties on the alloy. The impact of composition on materials performance is reviewed.