owns and operates the P. M. & B. quarry as well as the famous Empire hole. Limestone of the P. M. & B. Quarry The fine-grained limestone quarried at the P. M. & B. quarry is commonly referred to as Indiana Limestone, named after the state where it is quarried. Indiana Limestone is more formally termed Salem limestone, which is the name of the geologic formation that consists of this carbonate rock. Salem Limestone is a grain stone that is Mississippian in age. The limestone at the P. M. & B. Quarry is 98.40 percent calcium carbonate, making it more pure than the average Salem Limestone in Indiana, which averages approximately 97 percent calcium carbonate. Throughout most of the P. M. & B. quarry the limestone has a uniform fine grain, with only a few irregular patches of coarser grained and crystalline stone. The fine grained oolitic limestone that is quarried from this site is covered by a layer of Mitchell limestone in some places. Although this covering layer can be difficult to remove by quarry workers, it has acted as a protective barrier for the underlying oolitic limestone and aides in preserving its high quality. The Indiana Statehouse not only houses the Indiana state stone sculpture, it is also clad in Salem Limestone. 35 out of the 50 Statehouses around the country also use Salem Limestone quarried by the Indiana Limestone Company. The P. M. & B. Quarry is most famous for the Empire hole. This particular hole was the source of limestone used for the Empire State Building in New York City. 35,017,500 pounds of limestone block were extracted from this part of the quarry in 1931 and shipped to Manhattan for the 102-story building. The Empire hole was also the source of stone used for the Empire State Building’s 2001 renovations. Condition The tread of one of the three caster wheels is missing, making the sculpture slightly lopsided. There is discoloration of the limestone on all top and bottom corners, likely from the oils of people's hands while they touch the block in order to spin it. The steel plate's black enamel is worn away in most areas. The top four corners of the cube have been worn or broken away since 1983. See also List of public art at the Indiana Statehouse List of U.S. state minerals, rocks, stones and gemstones List of Indiana state symbols