Calamine brass is a type of brass made using a specific alloying procedure that uses the zinc ore calamine directly rather than first purifying it to metallic zinc. It is a zinc carbonate and copper alloy that was once used to simulate gold. Although alloyed calamine brass had been in use for ages, direct zinc smelting appears to have been unknown in Europe until the mid-18th century, and metallic zinc was produced directly via reducing-atmosphere smelting in India and China from the 12th century CE onwards.
Calamine brass was first produced in the Neolithic period by heating zinc ore in the presence of copper. Brass is a copper-zinc alloy that was produced when methods for creating metallic zinc were unknown. The zinc vapors diffuse into the copper, resulting in the formation of the brass alloy. As the zinc component of brass, metallurgists employed calamine (really a combination of the practically indistinguishable zinc ores smithsonite and hemimorphite). The resulting brasses, which were made by heating a copper-calamine mixture to a high temperature for several hours (enabling zinc vapor to condense from the ores and permeate the metallic copper), contained a large amount of slag material caused by the non-zinc components of calamine.
Because of the usage of ore rather than metallic zinc, it was also difficult to achieve the appropriate final copper-to-zinc ratio. Cementation is the term for this procedure. By the 1st millennium BC, this brass manufacturing technology had spread throughout Asia Minor. Calamine brass manufacture lasted into the 18th century.
Calamine brass was created by combining two-sevenths fine copper, four-sevenths calamine, and one-seventh shruff in the following proportions: (old plate brass). Calamine brass was the first type of brass manufactured, most likely beginning in the first millennium BC, and was not displaced in Europe by other brass manufacturers until the 18th century. More refined processes were most likely created centuries before by Indian brass producers.
Much of Northern Europe’s medieval brass came from the area surrounding La Calamine, now Kelmis, in Belgium. Brass manufacture was introduced to England in 1587, when some members of the Corporation of Mineral and Battery Works gained a license from the company (whose monopoly it was) to erect a brass works at Isleworth. However, a decade later, the business prevented the owners from mining calamine. According to a sign at Tintern Abbey, the well-known brassworks at this location began around 1568.
In 1649, a German immigrant erected a new brass factory in Esher, most likely utilizing Swedish copper. Following the passage of the Mines Royal Act in 1689, further works were constructed near Bristol, where brass manufacture grew to become a major industry in the 18th century. Cheadle and Birmingham were later brass producing sites in England.
Calamine brass was gradually phased out as zinc smelting processes in Europe progressed, producing metallic zinc that was more suitable for brass manufacturing than calamine. However, the transition away from calamine brass production was slow; a British patent was granted to William Champion in 1738, but the alloying of metallic zinc and copper to produce brass was not patented until 1781 (by James Emerson), and calamine brass mills were still in operation in South Wales as late as 1858. The sluggish adoption of this technology was most likely due to economic factors.
