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 Duke George the Bearded, it has been held annually since. Also interesting is Ore Mountain cuisine, which is simple, but rich in tradition. Since 1998 the Ore Mountains have striven to achieve UNESCO World Heritage status as the Ore Mountain Mining Region ("Montanregion Erzgebirge"). Ore Mountains The Ore Mountains or Ore Mountain Range () ( ; ; both literally "ore mountains") in Central Europe have formed a natural border between Saxony and Bohemia for around 800 years, from the 12th to the 20th centuries. Today, the border between Germany and the Czech Republic runs just north of the main crest