Cinnabar akin to that of HgO: each Hg center has two short Hg−S bonds (each 2.36 Å), and four longer contacts (with 3.10, 3.10, 3.30, and 3.30 Å separations). In addition, HgS is found in a black, non-cinnabar polymorph (metacinnabar) that has the zincblende structure. Cinnabar generally occurs as a vein-filling mineral associated with recent volcanic activity and alkaline hot springs. Cinnabar is deposited by epithermal ascending aqueous solutions (those near surface and not too hot) far removed from their igneous source. It is associated with native mercury, stibnite, realgar, pyrite, marcasite, opal, quartz, chalcedony, dolomite, calcite and barite. Cinnabar is
Ore Mountains sharply defined because the Ore Mountains, a typical example of a fault-block, descend very gradually. The topographical transition from the Western and Central Ore Mountains to the loess hill country to the north between Zwickau and Chemnitz is referred to as the Ore Mountain Basin; that from the Eastern Ore Mountains as the Ore Mountain Foreland. Between Freital and Pirna, the area is called the Dresden Ore Mountain Foreland ("Dresdner Erzgebirgsvorland") or Bannewitz-Possendorf-Burkhardswald Plateau ("Bannewitz-Possendorf-Burkhardswalder Plateau"). Geologically the Ore Mountains reach the city limits of Dresden at the Windberg hill near Freital and the Karsdorf Fault. The V-shaped valleys of