Augite is a common rock-forming mineral that belongs to the pyroxene group. It is a silicate mineral that is mainly composed of calcium, magnesium, iron, aluminum, and oxygen. Augite occurs in igneous rocks such as basalt, gabbro, andesite, and diorite, and occasionally in metamorphic rocks as well. It has a hardness of 5 to 6 on the Mohs scale and typically appears in shades of black, greenish-black, or dark brown.
Augite has a prismatic, tabular, or short columnar crystal structure and often exhibits distinct cleavage angles. It has a vitreous to glossy luster and tends to have a submetallic sheen on its cleavage surfaces. It also commonly exhibits striations on its crystal faces. Augite is often found intergrown with other minerals such as feldspars, pyroxenes, and amphiboles.
In terms of its physical properties, augite has a high density and moderate melting point, making it an important mineral for understanding the formation and evolution of igneous rocks. It forms as a result of the crystallization of molten rock, or magma, and can help geologists determine the cooling history and composition of the parent igneous rock.
Additionally, augite has been utilized in a variety of applications. Its hardness and durability make it suitable for cutting into gemstones for use in jewelry, although it is not widely used for this purpose. Its presence in certain volcanic rocks can indicate the potential for economic mineral deposits, and its identification in geological samples can assist in the study of the Earth's processes and history.
