Pyrokseeneihin

Pyrokseeneihin is a Finnish term referring to pyroxenes, a group of inosilicate minerals. These minerals are essential components of many igneous and metamorphic rocks found in the Earth's crust and upper mantle. The general chemical formula for pyroxenes is XY(Si,Al)2O6, where X and Y are typically divalent cations such as magnesium, iron, manganese, calcium, sodium, or lithium.

Pyroxenes are characterized by their single-chain silicate structure, which distinguishes them from the double-chain silicates of the amphibole group. This structural difference leads to variations in their physical properties, including cleavage angles. Pyroxenes typically exhibit two cleavage directions that intersect at approximately 87 and 93 degrees, whereas amphiboles have cleavage angles closer to 56 and 124 degrees.

The pyroxene group is further divided into several important mineral series based on their chemical composition. Common examples include the clinopyroxenes, such as augite and diopside, and the orthopyroxenes, like enstatite and ferrosilite. The specific proportions of cations in their structure determine the exact mineral and its properties.

Pyroxenes play a significant role in understanding geological processes. Their presence and composition in rocks provide clues about the temperature, pressure, and chemical environment under which the rocks formed. For instance, the abundance of iron-bearing pyroxenes can indicate the oxidation state of the magma or metamorphic fluid. They are also found in meteorites, offering insights into the composition of extraterrestrial bodies.