Any of a large group of silicon-oxygen compounds that are widely distributed throughout much of the solar system.
The silicates make up about 95% of the Earth's crust and upper mantle, occurring as the major constituents of most igneous rock s and in appreciable quantities in metamorphic rocks. They also are important constituents of lunar samples, meteorites, and most asteroids. In addition, planetary probes have detected them on the surfaces of Mercury, Venus, and Mars. Of the approximately 600 known silicate minerals, only the {{link=feldspar">feldspar s, amphibole s, pyroxene s, mica s, olivine s, feldspathoid s, and zeolite s are significant in rock formation.