Sand Good glass sand is over 99.5% silica (quartz). Silica, or silicon dioxide, is the most common glassforming oxide and the base for most glasses. The next most common glass-forming oxides are the oxides of boron and phosphorus.
SandGood glass sand is over 99.5% silica (quartz). Silica, or silicon dioxide, is the most common glassformingoxide and the base for most glasses. The next most common glass-forming oxides are theoxides of boron and phosphorus.