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 (steel wool), bundle drawn from larger diameter wire (smallest fiber is produced by this method), cast from molten metal, or grown around a seed (often carbon). Bundle drawn metal fiber can be produced to sizes smaller than one micrometre in diameter. Currently metallic fibers are manufactured primarily in Europe with only three manufacturers still producing metallic yarn in the United States. Metlon Corporation is one of the remaining manufacturers in the U.S. that stocks a wide variety of laminated and non-laminated metallic yarns & Brightex Corporation, Japan and South Korea, such as Hwa Young, is also manufacturing Metallic fibers. China