ortopyroxenes
Ortopyroxenes are a group of silicate minerals belonging to the pyroxene family. They are characterized by their orthorhombic crystal structure. Ortopyroxenes are solid solutions of magnesium and iron, with their chemical formula generally represented as (Mg,Fe)SiO3. The end-members of the ortopyroxene series are enstatite (Mg2Si2O6) and ferrosilite (Fe2Si2O6). In natural samples, intermediate compositions containing both magnesium and iron are common, often referred to by specific names such as bronzite and hypersthene depending on their iron content.
These minerals typically form in igneous rocks, particularly those that are relatively magnesium-rich, such as peridotites