Stalactites and Stalagmites form due to the precipitation of :

Stalactites and stalagmites are formed by water dripping or flowing from fractures on the ceiling of a cave. The dominant mineral in them is calcite (calcium carbonate) or CaCaO₃. Their largest displays are formed in caves of limestone and dolomite. Other minerals that may be deposited include other carbonates, opal, chalcedony, limonite, and some sulfides.