Aragonite is generally transparent or translucent, and colourless or white when pure. Impurities could cause shades of yellow, blue, pink, or green to happen. It can be found in a variety of habits: small, elongate, prismatic crystals form in radiating groups, and concretions and stalactites are also common. It has poor cleavage.
Found mainly in sedimentary environments, aragonite may form as tufa (porous rock) in Czechoslovakia and Turkey. Other localities include Spain, Colorado (USA), France and Cumbria (England).