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
Ore Mountains role on the Saxon side of the border. For example, in Hermsdorf/Erzgeb. in the Eastern Ore Mountains, calcite is mined, and near Lengefeld in the Central Ore Mountains, dolomite marble is extracted. For the first time in two decades, an ore mine was opened in Niederschlag near Oberwiesenthal on 28 October 2010. It is expected that 50,000-130,000 tons of fluorspar per year will be extracted there. In the Czech part of the Ore Mountains, tourism has gained a certain importance, even though the Krkonoše are more important for domestic tourism. In addition, mining still plays a greater role, particularly coal