Flowing films of water that move along floors or down positive-sloping walls build up layers of calcium carbonate (calcite), aragonite, gypsum, or other cave minerals. These minerals are dissolved in the water and are deposited when the water loses its dissolved carbon dioxide through the mechanism of agitation, meaning it can no longer hold the minerals in solution. The flowstone forms when thin layers of these deposits build on each other, sometimes developing more rounded shapes as the deposit gets thicker.