(From aurum,gold, and pig-inentum, paint,) also called arsenicum croceum, arseni-cumjlaxnim, adarnech, albimec althanaca, ethel; orpin, orpiment, and auripigment. Galen called it arseni-cum, and Scrapion narueth.
There are three kinds of orpiment; the gold coloured; the deep red mixed with yellow, called andarac, auripigmentum rubrum; and the greenish and yellowish, which is the least valuable. The best is a yellow shining sulphureous mineral, consisting of little flakes or scales like talc. If powdered orpiment is set on fire, it will flame, and yield the odour of common brimstone; if a plate of copper is held over these fumes at their first rising, it becomes white and brittle; an iron plate is also turned white by them; and it is soluble in oil. But, as is the case with crude antimony, its sulphureous combination is such as to render the arsenic inert. If it is kept long in a subliming vessel over the fire, the whole mass is raised, and concretes in the upper part of the vessel into a red pellucid substance like a ruby, leaving only a very small portion of metallic earth at the bottom.
Some use it for fumigating venereal ulcers; Drs. Boerhaave, Mead, and others, commend its fumes in asthmas; mixed with quick lime it hath been used as a depilatory. The painters use it for a gold colour, without the idea of its being poisonous; but if swallowed, its effects are similar to those of the hydrargyrus mu-viatus.
Auripigmentum hubrum. See Realgar.