This means formations that are made up of minerals. The Stalactite is an icicle-shaped formation that hangs from the ceiling of a cave, and is produced by precipitation of minerals from water dripping through the cave ceiling. To remember this just look at the word, it has tite spelled out and it needs to hold on tight to the ceiling for it to be identified as a stalactite. Stalagmite is formed of calcium salts deposited by dripping water and often uniting with a stalactite.