Virtual Collection: Nesosilicates

Nesosilicates: Silicate Minerals with Isolated Tetrahedra

In this class of silicate minerals, the tetrahedra anions ([SiO₄]⁴⁻) are connected to cations, rather than each other. Olivines, mentioned above, are a group of minerals that have this structure. One type of olivine is forsterite. Its chemical formula, Mg2SiO4, demonstrates that the silica tetrahedra are bonded to magnesium (Mg); in particular, each tetrahedron shares four Mg2+ cations. The atomic-level crystal structure of forsterite is shown in the interactive model below. Note in the model that the silica tetrahedra (shaded white) do not connect directly with each other; instead, they are isolated.

Crystal structure of Forsterite {111} by Museum of Mineralogy and Petrography, UAIC on Sketchfab

Atomic-level crystal structure of the mineral forsterite (Mg2SiO4). Model by Museum of Mineralogy and Petrography, UAIC (Sketchfab).

Olivine: (Mg,Fe)₂SiO₄

Dunite by EDUROCK – EDUCATIONAL VIRTUAL ROCK COLLECTION on Sketchfab

Sample of the rock dunite, which is composed mostly of green olivine minerals. Model by EduRock - Educational Virtual Rock Collection (Sketchfab; Creative Commons Attribution 4.0 International license).

Garnet Group: General Formula is A₃B₂(SiO₄)₃

Garnet by Digital Atlas of Ancient Life on Sketchfab

Sample of an undetermined garnet-group mineral. Specimen is from the teaching collections of the Paleontological Research Institution (Sketchfab; Creative Commons Attribution 4.0 International license).

Zircon: ZrSiO₄

Zircon by nate_siddle on Sketchfab

Sample of the mineral zircon. Model by Nate Siddle and the University of Queensland School of Earth and Environmental Science (Sketchfab).