Heating stoves use several types of glass.  Stove glass breaks into large straight pieces. The product usually found in wood/coal/pellet and some gas stoves is a 1380 degree ceramic glass with a brand such as Pyroceram, Robax, or Neoceram.  Ceramic glass can be identified by its 3/16" thickness (although 1/8" thickness is an option), slight amber tint, and subtle orange peel texture.