Black Chasm Cavern was designated a National Natural Landmark by the National Park Service in 1976 after being recommended by local members of the National Speleological Society, and as such is considered a nationally significant natural area. Visitors to the cave are enchanted by the beauty of a wide variety of formations including stalactites, stalagmites, flowstones and the vast arrays of rare helictite crystals, for which Black Chasm Cavern is justly famous. Above ground, kids love our gemstone mining at our mining flumes right outside the Visitors Center. Everyone is guaranteed to find some real gemstones; the perfect start to a rock collection! See website for cave tour details and pricing.