Very simple ingredients are used for making glass. The simplest recipe of glass includes ordinary sand, lime and ash. By adding other ingredients the glassblower can influence the final qualities of glass: its colour, hardness, durability and the temperature in which it starts to soften. The most common medieval glass types were soda glass and so called ΓÇÿforest glassΓÇÖ, or Waldglas, which differed in their composition of the metal. Glass is a poor conductor of electricity, but otherwise its qualities can vary a great deal.
