Cinnabar of approximately 8.1. The color and properties derive from a structure that is a hexagonal crystalline lattice belonging to the trigonal crystal system, crystals that sometimes exhibit twinning. Cinnabar has been used for its color since antiquity in the Near East, including as a rouge-type cosmetic, in the New World since the Olmec culture, and in China since as early as the Yangshao culture, where it was used in coloring stoneware. Associated modern precautions for use and handling of cinnabar arise from the toxicity of the mercury component, which was recognized as early as ancient Rome. The name comes from
Cinnabar ("kinnabari"), a Greek word most likely applied by Theophrastus to several distinct substances. Other sources say the word comes from the "shangarf" (Arabicized as "zinjifra"), a word of uncertain origin. In Latin, it was sometimes known as "minium", meaning also "red cinnamon", though both of these terms now refer specifically to lead tetroxide. Cinnabar is generally found in a massive, granular or earthy form and is bright scarlet to brick-red in color, though it occasionally occurs in crystals with a nonmetallic adamantine luster. It resembles quartz in its symmetry. It exhibits birefringence, and it has the highest refractive index of