<P> Brass was produced by the cementation process where copper and zinc ore are heated together until zinc vapor is produced which reacts with the copper . There is good archaeological evidence for this process and crucibles used to produce brass by cementation have been found on Roman period sites including Xanten and Nidda in Germany, Lyon in France and at a number of sites in Britain . They vary in size from tiny acorn sized to large amphorae like vessels but all have elevated levels of zinc on the interior and are lidded . They show no signs of slag or metal prills suggesting that zinc minerals were heated to produce zinc vapor which reacted with metallic copper in a solid state reaction . The fabric of these crucibles is porous, probably designed to prevent a buildup of pressure, and many have small holes in the lids which may be designed to release pressure or to add additional zinc minerals near the end of the process . Dioscorides mentioned that zinc minerals were used for both the working and finishing of brass, perhaps suggesting secondary additions . </P> <P> Brass made during the early Roman period seems to have varied between 20% to 28% wt zinc . The high content of zinc in coinage and brass objects declined after the first century AD and it has been suggested that this reflects zinc loss during recycling and thus an interruption in the production of new brass . However it is now thought this was probably a deliberate change in composition and overall the use of brass increases over this period making up around 40% of all copper alloys used in the Roman world by the 4th century AD . </P> <P> Little is known about the production of brass during the centuries immediately after the collapse of the Roman Empire . Disruption in the trade of tin for bronze from Western Europe may have contributed to the increasing popularity of brass in the east and by the 6th--7th centuries AD over 90% of copper alloy artefacts from Egypt were made of brass . However other alloys such as low tin bronze were also used and they vary depending on local cultural attitudes, the purpose of the metal and access to zinc, especially between the Islamic and Byzantine world . Conversely the use of true brass seems to have declined in Western Europe during this period in favour of gunmetals and other mixed alloys but by about 1000 brass artefacts are found in Scandinavian graves in Scotland, brass was being used in the manufacture of coins in Northumbria and there is archaeological and historical evidence for the production of calamine brass in Germany and The Low Countries, areas rich in calamine ore . </P> <P> These places would remain important centres of brass making throughout the medieval period, especially Dinant . Brass objects are still collectively known as dinanterie in French . The baptismal font at St Bartholomew's Church, Liège in modern Belgium (before 1117) is an outstanding masterpiece of Romanesque brass casting, though also often described as bronze . The metal of the early 12th - century Gloucester Candlestick is unusual even by medieval standards in being a mixture of copper, zinc, tin, lead, nickel, iron, antimony and arsenic with an unusually large amount of silver, ranging from 22.5% in the base to 5.76% in the pan below the candle . The proportions of this mixture may suggest that the candlestick was made from a hoard of old coins, probably Late Roman . Latten is a term for decorative borders and similar objects cut from sheet metal, whether of brass or bronze . Aquamaniles were typically made in brass in both the European and Islamic worlds . </P>

Where is brass used as an alternative to copper