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
Cinnabar moth moult (instars) they mainly feed on the leaves and flowers of the plant, and can be seen out in the open during the day. Like several other Arctiidae larvae, cinnabar caterpillars can turn cannibalistic. This is mainly due to lack of food, but they can eat other cinnabar larvae. Initially, the larvae are pale yellow, but later larval stages develop the jet black and orange/yellow striped colouring. They can grow up to , and are voracious eaters; large populations can strip entire patches of ragwort clean, a result of their low predation. Often, very few survive to the pupal stage,