Indiana Caverns the calcium carbonate precipitates out of the water. The calcium carbonate, in the form of the mineral calcite, a solid, crystallizes onto the bottoms and sides of existing stalactites, stalagmites, helictites, and sheets of flowstone to grow the formations over time. Other minerals are brought into the cave by flowing of water to create white, red, tan, and gray colors on the formations and walls. St. Louis Limestone is primarily made of calcite, but is also known to contain magnesium sulfate, manganese dioxide, ferric oxide, gypsum, dolomite, and aragonite. On the show tour, deposits of calcite, manganese dioxide, and ferric
Speleogen Speleogen A speleogen is a geological feature within a karst system that is created by the dissolution of bedrock. As rain water falls through the atmosphere it picks up carbon dioxide and more as it passes through organic material in the soil. As water moves through joints and cracks in calcium carbonate bedrock, more dissolution of the bedrock occurs and the bedrock features that are left are the speleogens. This process called speleogenesis is what leads to secondary formations or speleothems. The United States Code defines speleogens as "relief features on the walls, ceiling, and floor of any cave or