Stalagmites are mineral formations that grow upward from the floor of caves. They are created by the deposition of minerals from dripping water, which leaves behind tiny amounts of minerals as it evaporates. Over time, these deposits accumulate, forming a structure that can vary in size and shape. Unlike stalactites, which hang from the ceiling of caves, stalagmites rise from the ground. Both formations are made primarily of calcium carbonate, but stalagmites can also contain other minerals. The growth of stalagmites is a slow process, often taking thousands of years to develop even a few inches.