Metacinnabar

Metacinnabar is the cubic form of mercury sulfide (HgS). It is the low temperature form and trimorphous with cinnabar (trigonal structure) and the high temperature hypercinnabar (hexagonal structure). It occurs with cinnabar in mercury deposits and is associated with native mercury, wurtzite, stibnite, marcasite, realgar, calcite, barite, chalcedony and hydrocarbons.