Crystals are short prismatic and thick tabular , but are extremely rare.
Most commonly occurs as botryoidal or stalactitic masses and as fibrous veins , but also occurs encrusting , massive , as tiny, slender needles, and lenticular . It exists only in arid regions and dry caves which are protected from moisture. It commonly forms stalactitic and botryoidal growths on the walls and ceiling of mine tunnels from oxidation of copper sulfides. Chalcanthite specimens must be kept away from water and moist conditions, for a chemical effect with water causes them to eventually crumble or dissolve. Most specimens are very fragile, and much care should be taken when handling them.