The Medieval and Later European Brass Industry

John Champion patented in 1758 the process of producing brass and zinc from the common ore of zincblende (ZnS) or black jack (patent number 726). This ore had previously been considered worthless, but even with this advance it is obvious that metallic zinc was still far too expensive to use in brass production by direct mixing, a process which was patented by James Emerson in 1781 (no. 1297). Watson (1786), however, describes the use of zinc in the production of high-quality gilding brasses such as pinchbeck, tomback and Mannheim gold (see below). 

In the closing years of the production of calamine brass, the following grades of brass are recorded by Aitken (1866)  

BB - made of best copper. Latterf or sheet brass with 33% Zn as nearly as possible  

AM - some copper and calamine - tainted with lead ( )  

More helpfully, the various qualities of gilding metals in use during the 18th and 19th Centuries are listed by Lones (1919)  

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