Stalactite << stuh LAK tyt or STAL uhk tyt >> is a beautiful stone formation found in some limestone caves. Stalactites hang from the walls or roofs of the caves. Most look like large icicles, but some resemble draperies or straws with a hole through their center.
Most stalactites form when ground water rich in carbon dioxide dissolves the mineral calcite (calcium carbonate) from limestone directly above the cave. As the water drips into the cave, it loses carbon dioxide to the cave atmosphere and leaves behind minute quantities of calcite. The calcite accumulates very slowly, forming stalactites. In many cases, this process occurs over thousands of years.
Formations that build up from the floor of a cave are called stalagmites (see Stalagmite). In the United States, excellent examples of stalactites and stalagmites exist in Carlsbad Caverns in New Mexico, Luray Caverns in Virginia, Mammoth Cave in Kentucky, Cumberland Caverns in Tennessee, and Blanchard Springs Caverns in Arkansas.
