Definition of Glass of antimony

Glass of antimony, vitrum antimonii, is a transparent glass created from a preparation of antimony, historically used as an emetic. It was created using crude antimony, ground and calcined by a vehement fire, in an earthen crucible, until it no longer fumed, indicating that its sulfur was evaporated. The remaining substance (calx) was then vitrified in a wind furnace, upon which it became transparent, ruddy, and shining.