朱砂又称辰砂、丹砂、赤丹、汞沙，是硫化汞的天然矿石，大红色，有金刚光泽至金属光泽，属三方晶系。

朱砂产于石灰岩，板岩，砂岩中。分布于湖南、湖北、四川、广西、云南、贵州。

Cinnabar and cinnabarite (pronounced /ˈsɪnəbɑːr/ and /sɪnəˈbɑːraɪt/), likely deriving from the Greek κινναβαρι (kinnabari), refer to the common bright scarlet to brick-red form of mercury(II) sulfide, formula HgS, that is the most common source ore for refining elemental mercury, and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments.