Hexagonal prisms, often twinned, up to several cm are found in Triassic marls and clays outcrops around the village of Molina de Aragón. Local name: 'torrecillas' (little towers).
Werner (1796) described the species with samples coming from Molina de Aragón. He wrongly attributed the village to the region of Aragón, although it actually belonged to what today is the province of Guadalajara in Castile-La Mancha (Castilla-La Mancha), Spain.