Aegirine is a mineral belonging to the pyroxene group, primarily composed of sodium, iron, and silicon. It typically forms in igneous rocks and is known for its dark green to black color, often exhibiting a glassy luster. Aegirine is commonly found in alkaline environments, such as nepheline syenites and carbonatites, and can be associated with other minerals like amphibole and feldspar. This mineral is named after Aegir, the Norse god of the sea, reflecting its occurrence in volcanic regions. Aegirine is not only of interest to mineral collectors but also has applications in geology and petrology, helping scientists understand the formation of certain rock types.