The term for the mineral deposits that form in caves is stalactites and stalagmites. These formations occur through the deposition of minerals, typically calcium carbonate, from dripping water. Stalactites hang from cave ceilings, while stalagmites grow from the ground. The formation process is a slow one, taking hundreds to thousands of years, resulting from the constant dripping of mineral-rich water. These features can provide valuable insights into geological history and cave ecosystems.