Definition: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.
note X ref: do not confuse with SILICON; TN 172: differentiation among silic- terms; see MeSH definition for names of common forms of silicon dioxide
ExamplesDiatomaceous Earth; Quartz