Silicon Dioxide

**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.

**Tree numbers:** - D01.578.750 - D01.650.550.825 - D01.837.725

**Synonyms:** - Cristobalite - Silica - Tridymite