The Holston Formation

Geologic formation

A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...

, alternately known as the Holston Limestone, is a stratigraphic unit

Geologic unit

A geological unit is a volume of rock or ice of identifiable origin and age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features that characterize it....

 of Ordovician

Ordovician

The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

 age within the Chickamauga Group in the Ridge-and-Valley physiographic province

Ridge-and-valley Appalachians

The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending from southeastern New York through northwestern New...

 of the southeastern United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. A 120 miles (193.1 km) long outcrop

Outcrop

An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...

 belt of the Holston in East Tennessee

East Tennessee

East Tennessee is a name given to approximately the eastern third of the U.S. state of Tennessee, one of the three Grand Divisions of Tennessee defined in state law. East Tennessee consists of 33 counties, 30 located within the Eastern Time Zone and three counties in the Central Time Zone, namely...

 is the source of the decorative building stone known as Tennessee marble

Tennessee marble

Tennessee marble is a type of crystalline limestone found primarily 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, this stone has been used in the construction of numerous notable...

.

Near Knoxville

Knoxville, Tennessee

Founded in 1786, Knoxville is the third-largest city in the U.S. state of Tennessee, U.S.A., behind Memphis and Nashville, and is the county seat of Knox County. It is the largest city in East Tennessee, and the second-largest city in the Appalachia region...

 the Holston Formation is about 400 feet (121.9 m) thick but it thins toward the southwest; near Cleveland, Tennessee

Cleveland, Tennessee

Cleveland is a city in Bradley County, Tennessee, United States. The population was 41,285 at the 2010 census. It is the county seat of Bradley County...

 it is only 200 feet thick. The rock

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

 that is quarried for marble is a highly pure (97% CaCO₃) crystalline limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

, pink to cedar-red in color.

Use in building and sculpture

Among the notable buildings where Tennessee marble is used as a building stone are two in Washington, D.C.

Washington, D.C.

Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

: the National Gallery of Art

National Gallery of Art

The National Gallery of Art and its Sculpture Garden is a national art museum, located on the National Mall between 3rd and 9th Streets at Constitution Avenue NW, in Washington, DC...

, which uses stone from Knox

Knox County, Tennessee

Knox County is a county in the U.S. state of Tennessee. Its 2007 population was estimated at 423,874 by the United States Census Bureau. Its county seat is Knoxville, as it has been since the creation of the county. The county is at the geographical center of the Great Valley of East Tennessee...

 and Blount

Blount County, Tennessee

Blount County is a U.S. county located in the U.S. state of Tennessee. Its population was 123,010 at the United States Census, 2010. The county seat is at Maryville, which is also the county's largest city....

 counties, and the United States Capitol

United States Capitol

The United States Capitol is the meeting place of the United States Congress, the legislature of the federal government of the United States. Located in Washington, D.C., it sits atop Capitol Hill at the eastern end of the National Mall...

, which has stairways constructed from Hawkins County

Hawkins County, Tennessee

Hawkins County is a county located in the U.S. state of Tennessee. As of 2010, the population was 56,833. Its county seat is Rogersville, Tennessee's second-oldest town....

 marble.

General

• Mineral Commodities, in Mineral Resources of the Appalachian Region, U.S. Geological Survey and U.S. Bureau of Mines, Geological Survey Professional Paper 580, 1968.

External links

• Knoxville's marble past, Knoxville News Sentinel
  Knoxville News Sentinel
  The Knoxville News Sentinel is a daily newspaper in Knoxville, Tennessee, USA owned by the E. W. Scripps Company. It operates , an award-winning news website....
  
  , August 26, 2008 (article and videos)