Stalactite and Stalagmite

Stalactite and Stalagmite, mineral formation frequently found in caves. A stalactite is an icicle-shaped mass of accumulated calcium carbonate hanging from the roof or sides of a limestone cavern; it is formed by mineral precipitation from groundwater that has seeped, very slowly, through the roof of the cavern. Water circulating through the ground above a cavern picks up calcium bicarbonate as it percolates through the limestone. When the water trickles through the ground to the roof of a cavern, it tends to cling to the roof in droplets; as the droplets lose some of their water and carbon dioxide, calcium carbonate is precipitated and forms a deposit. As more water seeps through the roof, the precipitation of calcium carbonate continues and the deposits grow in length and width, forming stalactites; these are often of enormous size and beautiful shape.

Pure calcium carbonate is white, but stalactites are often variously colored by impurities in the mineral. Some of the water seepage also falls to the floor and there accumulates into calcium carbonate masses resembling inverted stalactites. These deposits, growing upward from the floor, are called stalagmites. Stalactites and stalagmites often occur in pairs and meet, forming columns that may grow as large as 1.5 m (5 ft) in diameter.