stalactite ornament, type of ornament characteristic of Islamic architecture. Generally executed in wood or in plaster over a wood or brick base, it consists of little vertical polygonal or curved niches rising and projecting in rows above one another in such a way as to create a general prismatic, corbeled form. Ingenious and intricate compositions of these elements are possible, and such purely geometric decoration was particularly acceptable to the Muslims in view of the Qur'an's prohibition of the use of natural forms. The primary use of stalactites was to form pendentives in the corners of a square room to receive the base of a circular dome, though this use was relatively infrequent in the Spanish Muslim style. Absent from the earlier Muslim buildings, they came into general use everywhere early in the 12th cent., forming cornices and the caps of posts and columns, decorating the heads of niches, and supporting the projecting balconies of minarets. In the interior of the Alhambra at Granada, Spain (13th–14th cent.), stalactites appear in particularly beautiful arrangements, especially in the decoration of arches and in the fantastic honeycombed ceiling vaults.