Crystal is a type of glass made from fine sand mixed with a metal oxide, lead oxide, which causes the sample Crystal refraction well when fashioned using a square corner.
Crystal is a type of glass Made of fine sand mixed with metal oxides. The lead oxide crystals refract light, which makes it well when cutting a corner.
The crystal is a kind of glass Production of fine sand mixed with metal oxide compounds As the lead oxide, which makes the crystal refraction of light well when the grinding is a square corner