"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)NCI" . "Hazardous or Poisonous Substance"^^ . . "Quso F-22BRNCI" . "Silica"^^ . "ETJ7Z6XBU4"^^ . . "SILICON DIOXIDEPTFDAETJ7Z6XBU4" . . "Silicon Dioxide"^^ . "Cab-O-Sil M-5PBRNCI" . "Inorganic Chemical"^^ . "C29853"^^ . "7631-86-9"^^ . "Silicon Dioxide"^^ . . "FDA"^^ . "CHEBI:30563"^^ . "SilicaSYNCI" . "C0037098"^^ . . "2O.Si"^^ . "Light Anhydrous Silicic AcidSYNCI" . . "Colloidal Silicon DioxideSYNCI" . "Silicon DioxidePTNCI" .