- silica, silicon oxide, silicon dioxide - 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
--1 is a kind of oxide
--1 is a substance of quartz; cristobalite; tridymite; lechartelierite
--1 has particulars: chert; flint; silex