Silicates form the largest and geologically most important group of minerals. A very large part of the Earth’s crust consists of silicate minerals, which occur as essential components of igneous, metamorphic and sedimentary rocks. The structural basis of silicates is formed by silicon-oxygen units, whose different modes of linkage give rise to an exceptionally wide variety of mineral structures.

Within the silicates, several structural groups are distinguished. These include nesosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates and tectosilicates. This classification is based on the way in which silicon-oxygen tetrahedra are linked to one another. The resulting structural diversity leads to very different chemical compositions, crystal forms and physical properties.

Silicates include numerous important rock-forming mineral groups such as feldspars, micas, pyroxenes and amphiboles. In addition, the class comprises many other minerals that occur in pegmatites, hydrothermal systems, metamorphic rocks, skarns, volcanic rocks or as secondary mineral formations.

Silicate minerals form under an exceptionally broad range of geological conditions. Some crystallize at high temperatures from magmatic melts, others form during metamorphic processes or from hydrothermal fluids. Still others develop through weathering processes or under near-surface conditions. As a result, this mineral class is of central importance both for rock formation and for the understanding of geological processes.

Germanates are considerably rarer than silicates. In their structural framework, germanium plays a role similar to that of silicon in silicates. Natural germanate minerals occur much less frequently and are usually associated with specialized geochemical conditions.

The class of silicates and germanates therefore comprises an exceptionally broad range of minerals, crystal structures and geological formation environments. The individual collector specimens in the Mineralien Weltweit range are documented with precise locality information, dimensions, weight and original photographs.