Virtual Cave

Helictites are contorted depositional speleothems which grow in any direction, seemingly defying gravity. They occur in many forms from tiny filaments (as in the top photo) to thick, antler-like forms (bottom photo). Most helictites are formed from calcite.

Helictites are formed by calcite-laden waters seeping through tiny pores in the rock. Hydrostatic pressure forces a small amount of the solution out, carbon dioxide is lost, and calcite is deposited. Growth continues through a tiny, central capillary chanel, which the solution flows through via hydrostatic and capillary pressure to emerge and deposit calcite at the tip.

Helictites are a very diverse group of speleothems, likely because different factors influence them. There is a very rare category that forms underwater, best known from Lechuguilla Cave, New Mexico. One show cave in California, Black Chasm Cavern, was designated a National Natural Landmark because of this. Visit our special tribute page to this cave’s diverse helictites.

The twisted shapes are due to many factors, including:

(1) impurities in the deposited calcite

(2) wedge-shaped crystals causing uneven deposition

(3) plugging of the central channel may occur in dry periods, and when flow resumes, the pressure may force a new channel out the side of the original one

(4) air currents may favor growth in a particular direction. Sometimes helictites are found facing the same direction down a passage (see upper left photo in thumbnail table below).