Cinnabar in Quartz beautiful polished spheres from Peru.

The mineral cinnabar is a mercury sulfide with the chemical formula HgS. The gray, brown or dark red (vermilion) cinnabar has a bright red stripe color and a complete cleavage along the crystal plane [1010]. The crystal system is trigonal, the density is high at 8.1. The hardness is 2 to 2.5. Cinnabar is not radioactive. The rare metacinnaberite is still found in California. The chemical composition is the same as that of cinnabar, but the structure is different (namely cubic). The word cinnabar originally meant vermilion and comes from Persian (shangarf). It reached our language through Greek, Latin and French. Cinnabar mainly occurs in low-temperature hydrothermal veins. The type location and long an important source of mercury as ore is Almadén, Spain, where it was already mined by the Celts. Cinnabar is the most important mercury ore. Cinnabar was known in ancient times and had been used as a pigment in China for more than 1000 years. Mercury can be obtained from cinnabar by sublimating it at 583 °C (856 K). This releases liquid mercury.