SILICA DUST, CRYSTALLINE, IN THE FORM OF QUARTZ OR ...
1. Exposure Data. Silica, or silicon dioxide (SiO 2), is a group IV metal oxide, which naturally occurs in both crystalline and amorphous forms (i.e. polymorphic; NTP, 2005).The various forms of crystalline silica are: α-quartz, β-quartz, α-tridymite, β-tridymite, α-cristobalite, β-cristobalite, keatite, coesite, stishovite, and moganite (NIOSH, 2002).