silicatemineral

Silicate minerals are minerals that contain silicon-oxygen tetrahedra (SiO4) as their fundamental structural unit. They form the largest and most important class of minerals in Earth's crust, comprising the bulk of igneous, metamorphic, and sedimentary rocks. The SiO4 tetrahedra can link in different ways, yielding several structural groups.

The main silicate groups, categorized by tetrahedral linkage, are: nesosilicates (isolated tetrahedra, as in olivine and garnet); sorosilicates (paired tetrahedra, as in epidote); cyclosilicates (rings of tetrahedra, as in beryl); inosilicates (single chains, such as pyroxenes; double chains, such as amphiboles); phyllosilicates (sheets, such as micas and clays); and tectosilicates (frameworks, such as feldspars and quartz).

Occurrence and formation: Silicate minerals occur in all major rock types. They crystallize from silicate-rich magmas during igneous processes; they undergo mineralogical changes during metamorphism; and they form or concentrate during weathering and sedimentary processes, producing products like quartz crystals and clay minerals.

Properties and uses: Silicate minerals exhibit a wide range of colors, hardness, and cleavage patterns. Common examples include quartz (hard and chemically stable), feldspars (major rock-forming minerals in many rocks), micas (excellent cleavage), olivine (green to yellow-green), pyroxenes and amphiboles (dark-coloured, chain silicates), and garnet. Economically important silicates include quartz and feldspar for glass and ceramics, clays for ceramics and as adsorbents, and mica for electrical and industrial applications.