Jewel Cave National Monument

Jewel Cave National Monument, located within the Black Hills National Forest of southwestern South Dakota, covers 1,274 acres on a high rolling plateau. Established in 1908, the monument is known for its many caverns and chambers lined with a solid coating of sparkling calcite crystals, which consist of a common and widespread mineral, crystalline calcium carbonate. The underground site was discovered when a passerby noticed a whistle of wind coming from a small opening in the cliffs. The many chambers are lined with multicolored, pyramid-shaped calcite crystals of various size and color, ranging from pale green to darker green and bronze.