Group 12 element zinc and cadmium which makes geological separation unlikely. As a consequence, cadmium is produced mainly as a byproduct from mining, smelting, and refining sulfidic ores of zinc, and, to a lesser degree, lead and copper. One place where metallic cadmium can be found is the Vilyuy River basin in Siberia. Although mercury is an extremely rare element in the Earth's crust, because it does not blend geochemically with those elements that constitute the majority of the crustal mass, mercury ores can be highly concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury
Breinigerberg its calamine flora. The hill of "Schlangenberg" is 276 metres above sea level and originates in the former ore mine of Breinigerberg. Names like "Bleiweg", which means "Way of lead", even today, give hints to the history of the village. The calamine from the ore mine Breinigerberg was used exclusively in Stolberg for the production of brass. The history of Breinigerberg can be traced back to the Romans. Twenty five coins dated between 100 BC and the year 92/93 AD as well as remains of a Roman craftsmen settlement had been found in the village. The buildings show that the