Silicate mineral

They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.

[1][2][3] In mineralogy, the crystalline forms of silica (silicon dioxide, SiO2) are usually considered to be tectosilicates, and they are classified as such in the Dana system (75.1).

On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years.

These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis.

For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seawater.

The frustules of dead diatoms are a major constituent of deep ocean sediment, and of diatomaceous earth.

[citation needed] A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO2+n]2n−.

For example, in the mineral orthoclase [KAlSi3O8]n, the anion is a tridimensional network of tetrahedrums in which all oxygen corners are shared.

Lithium aluminium silicate mineral spodumene
Diatomaceous earth, a biogenic form of silica as viewed under a microscope. The imaged region measures approximately 1.13 by 0.69 mm.
Orthosilicate anion SiO 4−
4 . The grey ball represents the silicon atom, and the red balls are the oxygen atoms.
Nesosilicate specimens at the Museum of Geology in South Dakota
Kyanite crystals (unknown scale)
Pyrosilicate anion Si
2 O 6−
7
Sorosilicate exhibit at Museum of Geology in South Dakota
Cyclosilicate specimens at the Museum of Geology, South Dakota
Pezzottaite
Bazzite
Kaolinite
Silica family (SiO 2 3D network), β- quartz
Aluminosilicate family, the 3D model of synthetic zeolite ZSM-5
Quartz
Lunar ferroan anorthosite ( plagioclase feldspar) collected by Apollo 16 astronauts from the Lunar Highlands near Descartes Crater