Calamine brass a mixture of the virtually indistinguishable zinc ores smithsonite and hemimorphite) as the zinc component of brass. The resulting brasses, produced by heating a mixture of copper and calamine to a high temperature for several hours (allowing zinc vapor to distill from the ores and permeate the metallic copper), contained a significant amount of slag material resulting from the non-zinc components of calamine. The use of ore rather than metallic zinc also made it difficult to accurately produce the desired final proportion of copper to zinc. This process is known as cementation. Calamine brass was produced using proportions of two-sevenths
Metallic fiber also produces metallic yarns; the city Dongyang contains more than 100 factories, though some of these are home based production sites rather than conventional factories. Two of the more popular factories are Salu Metallic Yarn and Aoqi Textile. The most popular company in Europe is the company Wagner-Tech-Textile GmbH with the brand name Rexess, this company is probably the last company which is able to produce metallic yarn in EU. They have still machinery for production of supported and unsupported metallic yarn. The Lurex Company has manufactured metallic fibers in Europe for over fifty years. They produce a wide variety