Building stone is one of the world’s most important construction materials. It comes from natural stone deposits in the earth and is mined through quarrying. It is used as crushed or broken stone called crushed stone, or as dimension stone. Dimension stone is cut from large blocks and slabs into definite shapes and sizes.
Crushed stone accounts for about 99 per cent of all building stone. In highway construction, it is blended with tarlike substances such as asphalt to produce the type of pavement called blacktop. Crushed stone is also mixed with portland cement and sand to make concrete used in building foundations, frames and floors; streets; airfield runways; conduit blocks; and panels.
Dimension stone is used most often for finishing and decorating all types of structures. Constructors expect good dimension stone to last more than 100 years. The best dimension stone has few pores or air cells. Stone with open pores may chip and break if water freezes and expands in the pores. Dimension stone includes granite, limestone, sandstone, marble, and slate.
Granite
is one of the strongest building stones. But it is difficult to cut and handle because it is so hard. It is used in the construction of many public buildings. Granite can be polished to a glossy finish and is an excellent background for carvings and lettering.
Limestone
is a hard and lasting building stone that can be cut easily and shaped with saws, planes, and even lathes. These buff or gray stones are sometimes placed over the rough stonework of a building to make an attractive surface. Limestone is also used to tile floors, and for sills, steps, and trimming.
Sandstone
is easy to work and is used for the same purposes as limestone. Sandstone that is well-cemented with silica is probably more durable and weather-resistant than most other building stones.
Marble
is the most elegant building stone. Pure marble is white, streaked with veins of black, gray, green, pink, red, and yellow. Builders use marble to make monuments and tombstones, and to decorate stairways, hearths, floors, and as paneling.
Slate
is fine-grained rock that can be split easily into thin slabs and used for roofing shingles and flagstone flooring.
