Stalactite a cave it will drip down. When the solution comes into contact with air the chemical reaction that created it is reversed and particles of calcium carbonate are deposited. The reversed reaction is: An average growth rate is a year. The quickest growing stalactites are those formed by a constant supply of slow dripping water rich in calcium carbonate (CaCO) and carbon dioxide (CO), which can grow at per year. The drip rate must be slow enough to allow the CO to degas from the solution into the cave atmosphere, resulting in deposition of CaCO on the stalactite. Too fast
Speleothem bedrock or detritus, and/or deposited because of a unique set of conditions in a cave; i.e., the cave environment has influenced the mineral's deposition. 319 variations of cave mineral deposits have been identified. The vast majority of speleothems are calcareous, composed of calcium carbonate in the form of calcite or aragonite, or calcium sulfate in the form of gypsum. Calcareous speleothems form via carbonate dissolution reactions. Rainwater in the soil zone reacts with soil CO to create weakly acidic water via the reaction: As the lower pH water travels through the calcium carbonate bedrock from the surface to the cave