These formations are composed of aggregates of crystals which are fibrous or filament-like in nature. Most typically they are gypsum, but can be composed of a variety of other mineral salts like epsomite or halite. In form they are generally classified into four subtypes, hair, cotton, rope, and snow. The latter type results from a disintegration of any of the first three types. The lefthand photo shows a classic gypsum rope formation, from a cave in the Grand Canyon. The righthand photo shows a more cotton-like example from a cave in Tennessee. All fibrous formations form from saturated solutions being squeezed out of pores in the bedrock (usually limestone)and depositing at they hit air. They grow from the base, with pressure forcing the deposited sections out as new sections are formed. The size of the pores determines how thick the crystals are, finer pores forming cotton or hair and larger ones forming rope.

Back to:
	Created: December, 1998 Author: Dave Bunnell