The term "rhombohedral" refers to a specific type of crystal system characterized by three equal-length axes that are not perpendicular to each other. This geometric arrangement creates a shape resembling a rhombus, where the angles between the axes are oblique. Common examples of rhombohedral crystals include minerals like calcite and quartz. In addition to its significance in mineralogy, the rhombohedral structure is also important in various fields such as solid-state physics and materials science. Understanding this crystal system helps scientists study the properties and behaviors of different materials, including their electrical and optical characteristics.