Solutional cave and most abundant solutional caves are located in limestone. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation. These include flowstones, stalactites, stalagmites, helictites, soda straws, calcite rafts and columns. These secondary mineral deposits in caves are called "speleothems". Limestone dissolves under the action of rainwater and groundwater charged with HCO (carbonic acid) and naturally occurring organic acids. The dissolution process produces a distinctive landform known as "karst", characterized by sinkholes, and underground drainage. Solutional caves in this landform—topography are often called karst caves. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed
Calcium carbonate Currently calcium carbonate is used to neutralize acidic conditions in both soil and water. Since the 1970s, such "liming" has been practiced on a large scale in Sweden to mitigate acidification and several thousand lakes and streams are limed repeatedly. Calcium carbonate is also used in flue gas desulfurisation applications eliminating harmful SO and NO emissions from coal and other fossil fuels burnt in large fossil fuel power stations. Calcination of limestone using charcoal fires to produce quicklime has been practiced since antiquity by cultures all over the world. The temperature at which limestone yields calcium oxide is usually given