Cassiterite

Cassiterite is a tin oxide mineral and the primary ore of tin, renowned for its high luster and strong crystal forms. It commonly occurs as prismatic to blocky crystals, often with well-defined terminations. While typically brown to black, cassiterite can also appear in shades of reddish, yellow, or even colorless varieties. Cassiterite specimens are admired for their brilliance and sharp crystal faces, making them highly desirable among collectors. Significant finds are known from several important mineral localities worldwide.