- any of the largest group of mineral compounds, as quartz, beryl, garnet, feldspar, mica, and various kinds of clay, consisting of SiO2 or SiO4 groupings and one or more metallic ions, with some forms containing hydrogen. Silicates constitute well over 90 percent of the rock-forming minerals of the earth's crust.
- any salt derived from the silicic acids or from silica.
- a salt or ester of silicic acid, esp one of a large number of usually insoluble salts with polymeric negative ions having a structure formed of tetrahedrons of SiO 4 groups linked in rings, chains, sheets, or three dimensional frameworks. Silicates constitute a large proportion of the earth's minerals and are present in cement and glass
