Xiong Huang

Xiong Huang is realgar, the arsenic sulfide mineral with composition As4S4 (alpha-As4S4), a soft monoclinic mineral with a distinctive bright orange-red to ruby-red color, resinous to greasy luster, and a Mohs hardness of 1.5–2. It occurs as a low-temperature hydrothermal vein mineral, commonly in association with the related yellow arsenic sulfide orpiment (As2S3) and with stibnite and calcite, in deposits in Hunan, Guizhou, and other Chinese provinces. Medicinal-grade material is selected for bright red color and freedom from arsenolite (the more toxic oxidation product), then ground under water (never roasted, which converts it to highly toxic arsenic trioxide) to a fine powder. In traditional Chinese medicine realgar is acrid, bitter, and warm with toxicity, primarily applied externally to dry damp sores, scabies, ringworm, and snake and insect bites, and used internally in tiny doses to kill parasites. Modern practice strongly discourages internal use because of cumulative heavy-metal arsenic toxicity, and many jurisdictions restrict its sale.