nesosilikatët

Nesosilicates are a group of silicate minerals characterized by isolated SiO4 tetrahedra. These tetrahedra are not linked to each other, meaning they are surrounded by cations, typically metal ions. The general formula for nesosilicates is often expressed as M2SiO4, where M represents a cation, usually divalent.

The isolated nature of the SiO4 tetrahedra in nesosilicates leads to specific physical and chemical properties. These minerals tend to be denser and harder than silicates with more complex structures, such as chain or sheet silicates. They also often exhibit distinct cleavage patterns due to the arrangement of these isolated units within the crystal lattice.

Common examples of nesosilicates include olivine, which is a solid solution series between forsterite (Mg2SiO4) and fayalite (Fe2SiO4). Olivine is a major component of the Earth's upper mantle. Other well-known nesosilicates include garnets, which form a group of minerals with a general formula X3Y2(SiO4)3, where X and Y are different cations. Zircon (ZrSiO4) and staurolite are also important members of this mineral group.

Nesosilicates are found in a variety of geological environments, from igneous and metamorphic rocks to meteorites. Their presence and composition can provide valuable information about the conditions under which they formed, including temperature, pressure, and the chemical environment.