Class XII
Silicates
Silicates are the most widespread minerals, composing 95% of the Earth's crust. They are the most important petrogenic minerals (feldspar, quartz, mica, amphiboles, pyroxenes, olivine, and others), and many of them are important raw materials in the non-metallic industry (ceramics, glass, construction materials).
Among silicates, there are also important ore minerals for beryllium, lithium, cesium, zirconium, nickel, zinc, and lanthanides. Some silicate minerals are distinguished by characteristics of gemstones-topaz, beryl (varieties emerald and aquamarine), quartz (amethyst), and others. The fundamental building blocks of the crystal lattice of silicates are SiO4 tetrahedra, which can be arranged and interconnected in different ways, and based on this, silicates are divided into nesosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, and tectosilicates.