a white or colorless vitreous insoluble solid; various forms occur widely in the earth's crust as quartz or cristobalite or tridymite or lechartelierite
a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth''s crust as quartz or cristobalite or tridymite or lechartelierite
a white or colorless vitreous insoluble solid (SiO2); various forms occur widely in the earth's crust as quartz or cristobalite or tridymite or lechatelierite
