Silica – 325 Mesh (very fine)

Used as a glass former in ceramic glazes, Silica (Quartz) is the best example of a natural mineral that is almost pure silicon dioxide (it is the most abundant mineral on planet Earth). Other ceramic minerals like feldspar and clay contain some ‘free silica’ (accessory quartz). However these also usually contain ‘silicates’, that is, SiO2 chemically combined with other oxides to form crystalline minerals.