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.

It has been considered the strongest emetic of any preparation of antimony. Yet, if dissolved in spirit of urine, it ceased to be either emetic or cathartic.