Cave Glossary

aragonite: like calcite, a crystallized form of calcium carbonate, but with a different crystal structure that results in more needlelike forms

calcite: a crystallized form of calcium carbonate, the chief component of blackboard chalk and antacid tablets, and the main constituent of limestone; occurs in caves in forms ranging from blocky masses to delicate crystals

cave pearl: a rounded, polished speleothem that arises where water drips into a hollow, growing concentric layers of calcite around a nucleus of sand

coralloid: a speleothem that is nodular, globular, or coral-like in shape and forms when thin films of mineral-laden water evaporate

dripstone: a speleothem, usually made of calcite, that forms when water droplets fall from a ceiling

flowstone: a speleothem that forms when thin films or trickles of mineralized groundwater precipitate a deposit, usually of calcite; forms sheets, draperies, and frozen waterfalls

frostwork: a speleothem consisting of radiating, needle-like crystals resembling frost

gypsum: a snow-white mineral made of calcium sulfate that is used in wallboard and plaster of paris, and in caves grows into all manner of forms, from gypsum "hair" to delicate flower shapes to massive sheets

raft: a thin layer of calcite that crystallizes on the surface of a cave pool, forming a sheet or free-floating fragments

raft cone: a stalagmite-like formation made of rafts that, under the weight of dripping water, break apart and settle in pieces to the bottom; where these pieces settle repeatedly at the same spot, cones build up

selenite: a transparent, crystalline form of gypsum

shelfstone: a shelf of stone that forms around the edges of cave pools and around the stalagmites within them

speleothem: a cave formation, specifically a secondary mineral deposit formed by the deposition of dissolved minerals, most commonly calcite

stalactite: a mineral deposit, usually of calcite, that forms from the cave ceiling downward from mineral-bearing solutions that seep from the ceiling

stalagmite: a mineral deposit, usually of calcite, that forms from the cave floor upward from mineral-bearing solutions that drip from the ceiling