tektosilicate

Tectosilicate, sometimes spelled tektosilicate, is a class of silicate minerals defined by a three‑dimensional framework in which all four oxygen atoms of each silicon tetrahedron are shared with neighboring tetrahedra. This complete linkage creates a highly polymerized, robust structure and makes tectosilicates the dominant framework silicates in the Earth's crust.

The defining feature is the SiO4 tetrahedral network that extends in all directions. Aluminum can substitute for silicon in the framework, and the resulting negative framework charge is balanced by interstitial cations such as potassium, sodium, or calcium. End-member examples include quartz (SiO2) and the feldspar group, with formulas such as orthoclase KAlSi3O8 and the plagioclase series NaAlSi3O8–CaAl2Si2O8. The broad feldspar family comprises alkali and plagioclase varieties, both of which are common rock-forming minerals.

Zeolites are another prominent subgroup of tectosilicates, featuring open, hydrated frameworks with channels and cavities that host water and other molecules. These porous structures underpin their use in ion exchange, catalysis, and adsorption.

Occurrence and significance: tectosilicates are among the most abundant minerals in Earth’s crust. Quartz and feldspars collectively constitute a large portion of continental rocks, contributing to common rock textures and weathering products. Their mechanical strength, chemical durability, and wide range of structural and compositional variants underpin many industrial applications, including glass and ceramic production, as well as specialized uses of zeolites in industry and environmental engineering.