Crystal Cave is a tourist cave just southwest of the town of Spring Valley in northeastern Pierce County, western Wisconsin, USA. This is an uncommon example of a dolostone network cave, developed in Ordovician-aged Prairie du Chien Group sedimentary rocks.

The stratigraphic succession at Crystal Cave is: - Willow River Dolomite (1st & 2nd levels of the cave) - New Richmond Sandstone (a relatively thin interval here) - Oneota Formation (3rd level/bottom level)

According to info. provided by Crystal Cave personnel, the travertine speleothem here is relatively young - <3000 years old, with most of it being <500 years old. Based on regrown broken speleothem from 1940s cave trail development, the speleothem growth rate here is estimated at about 1.5 inches per century.

Chert nodules and drusy quartz-lined cavities occur in the dolostone in places at Crystal Cave. Solution pockets are moderately common, which produce a moth-eaten appearance to the dolostone cave walls and ceilings. Larger rooms and passage intersections have apparent break-out domes developed in the ceiling. Cave passages are frequently developed along subvertical joints (see map - people.uwec.edu/jolhm/Cave2007/TeamC/TeamC/CrystalCave/Cr...).

Travertine speleothem occurs in some areas - principally dripstone (stalactites, stalagmites, columns) and flowstone. Some Crystal Cave travertine speleothem is fluorescent and even phosphorescent.