Roman metallurgy the most important being bronze, an alloy of copper and tin. Alloys are mixtures of different metals created either by smelting or by forging. It is important to note that an ore does not necessarily constitute an alloy; ore is a collection of minerals and alloyed metals. As metallurgical technology developed (hammering, melting, smelting, roasting, cupellation, moulding, smithing, etc.), more metals were intentionally included in the metallurgical repertoire. By the height of the Roman Empire, metals in use included: Gold, Silver, Copper, Tin, Lead, Zinc, Iron, Mercury, Arsenic, Antimony (Healy 1978). As in the Bronze Age, metals were used based
Antimicrobial copper-alloy touch surfaces in April 2011 analyzed the effectiveness of copper-alloy furnishings to lessen the microbial load on various frequently touched surfaces such as door handles, toilet seats, and railings. Of the 14 surfaces tested 8 had statistically significant decreases in the number of microbes found on them while the other 6 had a decrease in the number of microbes as well, but not in a statistically significant amount. Additionally certain microbes in particular were found in far less quantities on the copper-alloy surfaces than on the normal ones, these being Vancomycin-resistant "Enterococcus", "Staphylococcus aureus", and Coliform bacteria. The study concluded that copper