The most famous mineral is ice. It differs from other minerals in its light melting. Icicles are like stalactites that can be seen in deep caves. A stalactite icicle appears in places of cracks in the stone arch of caves. Water constantly flows from cracks in which calcareous salt is dissolved. Drops of this water evaporate, and in their place lay a layer of a real mineral, a stone, which can be of different colors.