Silica (SiO2) sand is easily obtainable on beaches, and manufacturers commonly use it to make glass. People usually crush sandstone or collect it from rivers and beaches. The purest form of silica has a fusion point of 1,760C (3,200F). However, impurities lower the melting point of sands used to extract silica. For high-melting-point casting like steel, one should use at least 98% pure silica. For lower-melting-point metals such as cast iron and non-ferrous
