Orpiment, Senduchen River, East Yakutia, Siberia, Russia

Orpiment is a deep-colored, orange-yellow arsenic sulfide mineral with formula As 2S3. It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and is formed both by sublimation and as a byproduct of the decay of another arsenic mineral, realgar. Orpiment takes its name from the Latin auripigmentum (aurum, "gold" + pigmentum, "pigment") because of its deep-yellow color. Orpiment was traded in the Roman Empire and was used as a medicine in China, even though it is very toxic. It has been used as fly poison and to tip arrows with poison.[citation needed] Because of its striking color, it was of interest to alchemists, both in China and the West, searching for a way to make gold. For centuries, orpiment was ground down and used as a pigment in painting and for sealing wax, and was even used in ancient China as a correction fluid. It was one of the few clear, bright-yellow pigments available to artists until the 19th century. However, its extreme toxicity and incompatibility with other common pigments, including lead and copper-based substances such as verdigris and azurite, meant that its use as a pigment ended when cadmium yellows, chromium yellows and organic dye-based colors were introduced during the 19th century. Orpiment is mentioned in the 17th century by Robert Hooke in Micrographia for the manufacture of small shot.