Pirokseenimineraalit

Pirokseenimineraalit constitute a significant group of rock-forming silicate minerals. They are characterized by a single chain silicate structure, which differentiates them from the double chain amphiboles. The general formula for pyroxenes is XY(Si2O6), where X and Y are cations that can vary, leading to a diverse range of compositions within the group. Key elements commonly found include magnesium, iron, calcium, sodium, and aluminum. Pirokseenit typically crystallize in the monoclinic or orthorhombic crystal systems. Their hardness generally ranges from 5 to 6.5 on the Mohs scale, and they often exhibit cleavage angles close to 90 degrees. Common colors for pyroxenes include green, brown, black, and sometimes colorless or pale pink. They are abundant in both igneous and metamorphic rocks, particularly in mafic and ultramafic igneous rocks like basalt and gabbro, and in high-grade metamorphic rocks. Important members of the pyroxene group include enstatite (MgSiO3), ferrosilite (FeSiO3), diopside (CaMgSi2O6), hedenbergite (CaFeSi2O6), and augite. The presence and type of pyroxenes in a rock can provide valuable information about the conditions under which the rock formed and its geological history.