Speleothem

Image: A huge pilar in Postojnska Jama, Slovenia.

speleothem: A secondary mineral deposited in a cave by the action of water. Also known as cave formation.
From: Sybil P. Parker ed. (1997): McGraw-Hill Dictionary of Geology and Mineralogy, 380 pages, McGraw-Hill; ISBN: 0070524327 amazon.com

The most common speleothems consist of calcite (CaCO₃), aragonite (CaCO₃) or gypsum (CaSO₄). Some common types are:

Boxwork		Thin plates of calcite forming boxes.
Cave Coral		Very small short stalks with bulbous ends, usually occurring in numbers in patches.
Cave Pearl		A smooth, polished and rounded speleothem found in shallow hollows into which water drips.
Column, Pillar		A speleothem from floor to ceiling, formed by the growth of a Stalactite and a stalagmite to join, or by the growth of either to meet bedrock.
Curtain, Shawl, Bacon Rind		A speleothem in the form of a wavy or folded sheet hanging from the roof or wall of a cave, often translucent and resonant.
Diadochite \|		speleothems looking like stalactites and stalagmite, found in mines, growing extremely fast.
Dogtooth Spar		huge calcite cristals forming crusts on floor and walls, formed in standing water.
Helictite, Eccentric		A speleothem of abnormal shape or attitude.
Moonmilk, Rockmilk		A soft, white plastic mineral consisting of Calcite, hydrocalcite, hydromagnesite or huntite.
Pillar		A dripstone where the stalactite- and stalagmite-part are grown together.
Rimstone Pool		Pools with very thin calcite rims.
Shield		a calcite conretion in the form of a thin disc, a circuar plate forming at the wall.
Stalactite		A dripstone hanging downwards from a roof or wall, of cylindrical or conical form, usually with a central hollow tube.
Stalagmite		A dripstone projecting vertically upwards from a cave floor and formed by precipitation from drips.
Stegamite
Straw (-stalactite)		A long, thin-walled tubular Stalactite less than about 1cm in diameter.

Speleothem

See also