Famous Building Stones of Our Nation’s Capital The buildings of our Nation’s Capital are constructed with rocks from quarries located throughout the United States and many distant lands. The earliest Government buildings, however, were constructed with stones from nearby sources because it was too difficult and expensive to move heavy materials such as stone any great distance without the aid of modern transportation methods, including large cargo ships, trains, and trucks. This Fact Sheet describes the source and appearance of three local stones commonly used in building Washington, D.C.

Aquia Creek Sandstone: White House, Capitol Building, and Gatehouses The Aquia Creek sandstone, also quality of toughness without brittle hard- called “freestone,” was a popular build- ness. In appearance, the coarse-grained ing material between 1790 and 1840. It stone is light gray or tan, and it is streaked was prized for construction because of or clouded with buff, yellow, or red colors the ease with which it could be carved that give it a warm tone. and transported to building sites along Unfortunately, the Aquia Creek the Potomac River. George Washington sandstone proved to have quality-related selected the Aquia Creek sandstone flaws, and it weathered poorly. After the as the primary material for use in burning of the White House and Capitol Government buildings. In 1791, and buildings by British troops in 1814, the acting on the Government’s behalf, walls made of Aquia Creek sandstone USGS Laura Corey, Pierre L’Enfant—the architect and engi- suffered cracking and pitting. Both build- Aquia Creek sandstone neer selected to design the new city of ings were whitewashed and later painted Washington, D.C.—purchased a quarry to mask the damage and help protect the about 40 miles south of Washington along stone from weathering. As the defects Aquia Creek in Stafford County, Virginia. of the stone became apparent, its use for (The peninsula on which the quarry is exteriors declined. One of the last major located subsequently became known as exterior uses of the stone was at the Government Island and today is a natural U.S. Capitol gatehouses and gateposts park preserve and archaeological site.) (circa 1827). One of these gatehouses Stone from this quarry was used for the and three of the gateposts are located at original portions of the President’s House 15th Street and Constitution Avenue NW, (later known as the White House), some and another gatehouse is located farther older portions of the U.S. Capitol building, west at 17th Street NW. USGS Laura Corey, the oldest portions of the U.S. Treasury Interior use of the Aquia Creek sand- U.S. Capitol gatehouse building, and numerous other smaller stone may also be seen in the U.S. Capitol, structures around the city. including in the walls and columns of the The Aquia Creek sandstone is of rooms adjoining the Rotunda and in the Early Cretaceous age (between 100 and spiral staircase. It was also used in the 140 million years old). It is composed pri- Little Rotunda tobacco column colon- marily of sand and pebble-sized quartz and nade in the Senate wing on the same floor, clay pellets and is cemented with silica. in the famous cornstalk columns in the Unlike many other sandstones, its matrix Senate vestibule, and downstairs in the is harder than its crystals, which gives it a Doric sandstone columns of the crypt. Laura Corey, USGS Laura Corey, White House U.S. Capitol U.S. Capitol gatepost

U.S. Department of the Interior Fact Sheet 2012–3044 Printed on recycled paper U.S. Geological Survey April 2012 Seneca Sandstone: Smithsonian Institution Main Building (the Castle) During the “brownstone era,” from Montgomery County just west of Seneca about 1840 to about 1880, red Seneca Creek. The remains of the quarry where sandstone was an extremely popular canal barges were loaded with stone for building stone in Washington. This stone shipment up or down the canal may still of Triassic age (more than 200 million be seen. The ruins of a quarry building years old) crops out along the Potomac that housed saws and machinery for fin- River in the Triassic lowlands from ishing the stone stand nearby. (Note: This Seneca, Maryland, to just east of Point of site is located on private land.) Rocks, Md. Red Seneca sandstone ranges The first important Government from reddish brown to a deep purplish building to be constructed of this sand- Smithsonian Castle brown. It is brightly colored when cut stone was the carved and turreted main but darkens and hardens on exposure building of the Smithsonian Institution to air. Seneca sandstone is generally (the Castle), which was built between fine-grained and uniform, and it does not 1847 and 1857. The sandstone, when easily scale when exposed to weather. first quarried, was described as lilac gray; Several quarries supplied this after years of oxidation, it is now a dark red sandstone to the city. The best red. Seneca sandstone is also promi- known is located about 20 miles up the nent on the floors and the Rotunda door USGS Laura Corey, Potomac River on the Maryland shore in frames in the U.S. Capitol. Seneca sandstone

Cockeysville Marble: Washington Monument Marble eventually replaced annulled in 1880. The extensive upper sandstone as the most popular building part of the monument was then finished stone in Washington. Of particular with marble from a quarry located north note were the three different kinds of of Baltimore in Cockeysville, Md. The regionally metamorphosed marbles of monument was completed in 1884, late Precambrian to early Paleozoic reaching a height of 555 feet and 5 inches. age that were used in the construction The three kinds of marble used of the Washington Monument. The in the monument can be distinguished first 152 feet of the monument, which by their differences in color. The lower was built between 1848 and 1854, is section is the white, coarse-grained, faced with marble from the quarry nearly pure calcium carbonate marble located at Texas, Md., just north of from the Texas, Md., quarry. The upper Baltimore in the Piedmont Province. section is built of fine-grained marble Cockeysville marble Work stopped when funds ran out. from the Cockeysville, Md., quarry. The When construction was about to resume Cockeysville marble is a clear white Sheffield marble in 1876, the builders discovered that stone with a few pale streaks or bands, the foundations were inadequate and and its higher magnesium content gives it that the monument was sinking and a pale gray sheen. Both marbles contain Texas marble tilting. To straighten and stabilize the veins and pockets of mica and pyrite, monument, wider subfoundations were which can stain the marble if it is exposed constructed to a depth of nearly 37 feet. to the elements. In between these two In 1879, work began again on the upward marbles are four rows of a pronounced projection of the monument, and four white marble from the Sheffield, Mass., courses, or rows, of white marble from quarry. Washington Monument Sheffield, Massachusetts, were laid above the Texas, Md., marble. Because This Fact Sheet is based on a more extensive of difficulties with timely delivery and U.S. Geological Survey publication, quality control of the marble, however, “Building Stones of Our Nation’s Capital,” the contract with the Sheffield quarry was at http://pubs.usgs.gov/gip/stones.

For more information, contact: U.S. Geological Survey

National Park Service Office of Science Quality and Integrity Cockeysville marble from the Washington 12201 Sunrise Valley Drive, MS 912 Monument showing damage caused by the Reston, VA 20192 August 2011 earthquake. Web site: http://education.usgs.gov