Stalagmite

A stalagmite (UK: /ˈstæləɡmaɪt/ or US: /stəˈlæɡmaɪt/; from the Greek σταλαγμίτης - stalagmitês, from σταλαγμίας - stalagmias, "dropping, trickling") is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites may be composed of lava, minerals, mud, peat, pitch, sand, sinter and amberat (crystallized urine of pack rats).

The corresponding formation hanging down from the ceiling of a cave is a stalactite. Mnemonics have been developed for which word refers to which type of formation; one is that stalactite has a C for "ceiling", and stalagmite has a G for "ground".