The chemical composition of realgar is AsS, also known as cockscomb stone, which contains 70.0% arsenic. It is mainly used to extract arsenic and arsenic compounds, and is the raw material for making pigments, fireworks, glass, etc. It is also used as a traditional Chinese medicine for detoxification and sterilization.

The realgar at the junction of Cili in China and Shimen in Hunan is the best in the world. Romania, Germany, Switzerland and other countries are also major producing areas.