Silicon Dioxide

**Semantic type:** Hazardous or Poisonous Substance|Inorganic Chemical

**Definition:** A natural compound of silicon and oxygen found mostly in sand, Silica has three main crystalline varieties: quartz, tridymite, and cristobalite. Fine particulate silica dust from quartz rock causes over a long-term progressive lung injury, silicosis. (NCI04)

**Synonyms:** - Cab-O-Sil M-5P - Colloidal Silicon Dioxide - Light Anhydrous Silicic Acid - Quso F-22 - SILICON DIOXIDE - Silica