In building construction, rock cut into blocks and slabs or broken into pieces.
It comes as hard as granite and as soft as limestone or sandstone. Where available, stone has generally been the preferred material for monumental structures. Its advantages are durability, adaptability to sculpting, and the fact that it can be used in its natural state. But it is difficult to quarry, transport, and cut, and its weakness in tension limits its use. The simplest stonework is rubble, roughly broken stones bound in mortar. Ashlar work consists of regularly cut blocks with squared edges. Building stone is quarried by sawing if it is soft, and split apart with wedges or by blasting if hard. Many devices are used to shape and dress stone, from handheld tools to circular saws, surfacing machines, and lathes. Some stones are strong enough to act as monolithic (one-piece) supports and beams; and in some styles (e.g., ancient Egyptian temples) stone slabs are employed even for roofing, supported by many closely spaced columns. Before the arch , builders were handicapped by the tendency of stone to break under its own weight. But stone in compression has great strength, and the Romans built huge stone bridges and aqueducts. Though stone has generally been abandoned for structural use in the 20th century, it is widely used as a thin, nonbearing surface cladding. See also masonry .