Tennessee marble is a type of crystalline limestone found only in East Tennessee, in the southeastern United States. Long esteemed by architects and builders for its pinkish-gray color and the ease with which it is polished, the stone has been used in the construction of numerous notable buildings and monuments throughout the United States and Canada, including the National Gallery of Art, National Air and Space Museum, and United States Capitol in Washington, D.C., the Minnesota State Capitol, Grand Central Terminal in New York, and Union Station in Toronto. Tennessee marble achieved such popularity in the late-19th century that Knoxville, the stone's primary finishing and distribution center, became known as "The Marble City." While Tennessee marble is not true marble, its crystalline nature lends it a strong resemblance to marble, especially when polished. The stone occurs in belts of Ordovician-period rocks known as the Holston Formation and is quarried primarily in Knox, Blount, Loudon, Union, and Hawkins counties. While pink is the most well-known color, the stone also occurs in gray, dark brown ("cedar"), and variegated shades. The use of Tennessee marble declined after World War II, when cheaper building materials became widely available. There are currently only six active quarries, all operated by the Tennessee Marble Company. The stone has most recently been used in the floor of the United States Capitol Visitor Center and for the 170-ton "First Amendment" tablet that initially adorned the facade of Washington's Newseum, as well as the National Constitution Center in Philadelphia, Pennsylvania.
Geology
Occurrence Tennessee marble is found in the Appalachian Ridge-and-Valley Province, a series of alternating elongate ridges and valleys that lie between the Blue Ridge Mountains and the Cumberland Plateau. The Holston Formation, in which Tennessee marble is found, occurs in a series of belts that follow the natural folds and faults of the ridges and valleys. While these belts can be up to 75 miles (121 km) long, they are rarely more than a few miles wide. In 1911, the Tennessee State Geological Survey identified six primary Holston Formation belts containing Tennessee marble: the Luttrell, Black Oak, Concord, Knoxville, Bays Mountain, and French Broad belts. A seventh belt, the Galbraith in Hawkins County, is considered an extension of the Black Oak. The Luttrell belt, the westernmost of the Holston Formation belts, stretches along Copper Ridge from Beaver Creek in Fountain City northeast to Galbraith Springs (about 10 miles (16 km) west of Rogersville) in Hawkins County. The Black Oak belt stretches along Black Oak Ridge from Monroe County to the Corryton area in north Knox County. The Concord belt, one of the most heavily quarried, stretches from Sweetwater through Knox County to Strawberry Plains. The Knoxville belt, also heavily quarried, stretches from southeast of Sweetwater to Ruggles Ferry (east of Knoxville) in Knox. The Bays Mountain belt is found along the southwestern end of Bays Mountain in south Knox County and stretches into northern Blount County. The French Broad belt is a u-shaped belt found at the confluence of the French Broad and Holston rivers ("Forks-of-the-River").
Lithology While true marble is metamorphic, Tennessee marble is sedimentary and is therefore classified as limestone. Tennessee marble was formed from the accumulation of bryozoan and other primordial marine lifeforms 460 million years ago, during the Ordovician period. Even when polished, the stone retains a fossiliferous texture, with bryozoan and crinoid fossils being among the most commonly found. A noticeable feature is the presence of jagged horizontal gray or black lines, or "stylolites." Known as "crowfeet" by quarrymen, these form from residual insoluble materials left over from the natural limestone dissolution processes. The most well-known shades are pink, gray, and cedar, but it also is found in blue, yellow, and cream shades. Along with its aesthetic colors, builders preferred the stone for its durability, the ease with which it is polished, and the fact that the stone is virtually impervious to stains. Tennessee marble is also easily converted into lime, and mid-20th century lime companies occasionally erected kilns near defunct quarries for this purpose.
History
As early as the late 18th century, Tennessee marble was being harvested for construction purposes, most notably for the Ramsey House on the outskirts of Knoxville and the "Old Stone House" near modern Friendsville. Visitors to East Tennessee were reporting the existence of marble beds in the region as early as the 1810s, and state geologist Gerard Troost provided an extensive description of Tennessee marble deposits in an 1831 report to the Tennessee General Assembly. The Rogersville Marble Company, founded in 1838, produced monuments and furniture stone extracted from a quarry in Hawkins County. Marble Hall, a house built by the company's director, Orville Rice, contained numerous Tennessee marble interior elements and acted as a showplace for the company. In 1850, Tennessee Governor William Trousdale chose the Rogersville Marble Company's marble as the state's representative stone for the construction of the Washington Monument. During this same period, marble from Hawkins County, either from Rice's quarry or a rival quarry south of Rogersville, was used in U.S. Capitol extension projects (William Dougherty, the construction superintendent for the Washington Monument, was instrumental in obtaining the marble). Transporting the quarried blocks out of the region presented a major challenge for these early companies. Mule teams, often led by local African American entrepreneurs, carried the blocks to the Holston River, where they were loaded onto flatboats and transported downstream.
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