Leucite is a mineral composed of potassium and aluminum silicate, commonly found in volcanic rocks. It typically appears as colorless or white crystals and is known for its glassy luster. Leucite is significant in geology as it helps scientists understand the conditions under which certain igneous rocks, like trachyte, form. This mineral is often associated with other volcanic minerals, such as feldspar and nepheline. Leucite's presence can indicate specific chemical compositions in magma, making it valuable for studying volcanic activity and the evolution of the Earth's crust.