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
Pete's Paradise Cave is possible to crawl through a tight hole for eight metres to come out at what was called "Pearl's Chamber" because of the presence of "Cave pearls". These are formed around grains of sand and they become coated with calcium carbonate which can grow in time to be 3 cm in diameter. A moving body of water is required to keep these pearls turning whilst they form. The last, and described as the best, chamber is the "Hall of Pillars". This chamber contains another perfect rimstone. This is one of three in this cave and only one of three in