Indiana limestone

Indiana limestone — also known as Bedford limestone — is a common regional term for Salem limestone, a geological formation primarily quarried in south central Indiana, USA, between the cities of Bloomington and Bedford.

Bedford, Indiana, has been noted to have the highest quality quarried limestone in the United States. Salem limestone, like all limestone, is a rock primarily formed of calcium carbonate. The limestone was deposited over millions of years as marine fossils decomposed at the bottom of a shallow inland sea which covered most of the present-day Midwestern United States during the Mississippian Period.

Native Americans were the first people to discover limestone in Indiana. Not long after they arrived, American settlers used this rock around their windows and doors and for memorials around the towns. The first quarry was started in 1827, and by 1929 Hoosier quarries yielded 12,000,000 ft³ (340,000 cubic meters) of usable stone. The expansion of the railroads brought great need for limestone to build bridges and tunnels and Indiana was the place to get it.

American architecture of the late 19th and early 20th century included a lot of limestone detail work on buildings, but as architectural styles changed, so did the demand for limestone. Salem limestone was officially designated as the state stone of Indiana by the Indiana General Assembly in 1971. With the Arab Oil Embargo of 1973, the price of alternative building materials skyrocketed so Indiana limestone reemerged as an energy-efficient building material.

Indiana limestone is part of a high-end market. It is mostly used on the exterior of homes and commercial buildings. With the impact of acid rain it is not used in monuments as it was in the 19th century. Many of Indiana's official buildings, such as the State capitol building, the monuments in Downtown Indianapolis, the Indiana University School of Law in Indianapolis, many buildings at Indiana University in Bloomington, and the Indiana Government Center, and most of the state's 92 courthouses are all examples of Indiana architecture made with Indiana limestone. Indiana limestone has also been used in many other famous structures in the United States, such as the Empire State Building, the Pentagon, Yankee Stadium, and the Washington National Cathedral. In addition, 35 of the 50 state capitol buildings are made of Indiana limestone.

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