or nitre also spelled saltpeter or niter
Transparent, colourless, or white powder or crystals of potassium nitrate (KNO 3 ), found native in deposits.
It is a strong oxidizing agent (see oxidation-reduction ), used in fireworks, explosive s, matches, fertilizers, glassmaking, steel tempering , and food curing; as a reagent; and as an oxidizer in solid rocket propellants. The term is also used for sodium nitrate (Chile saltpetre) and calcium nitrate (lime saltpetre), both of which are used in the nitric acid industry and as fertilizers, and for ammonium nitrate (Norway saltpetre), a high explosive and fertilizer.