17 Mart 2013 Pazar

Georgia State Stone

Georgia State Stone


Marble is a hard, generally massive (of uniform texture), crystalline rock formed from the metamorphism of limestone. Its chemical composition is thus identical to limestone’s, being mainly calcium carbonate (CaCO3). Impurities inherited from the parent limestone may include iron oxide, chert, silica, and magnesium; these result in variations in color and sometimes in swirls or veins.
An 1886 summary of Georgia’s marble industry reported on the variety of color in the four quarries of Pickens County:
The Kennesaw quarry yields a limited quantity of white marble, the crystals of which are large and glistening, but very compactly united; and in addition there is a white marble clouded with light spots and lines of blue. The Cherokee quarry produces white and bluish-gray stock, both clouded with dark-blue spots. From the Creole quarries a marble having a white ground and exceedingly dark-blue mottlings is taken. This is used for monumental work and exterior decorating. A great variety of different shades of marble is to be found in the Etowah quarry, the principal colors being pink, salmon, rose, and dark green.
While Georgia has never designated an official state stone, the admired Georgia marble from Pickens County represents the state well because of its fine quality and historic importance. The rock was discovered in about 1832 by an immigrant Irish stonemason, Henry T. Fitzsimmons, of Gwinnett County. He promptly set about purchasing land and developing quarries. These were successful, but on a scale limited by the means of transportation, which was the oxcart.
After 1883, the Marietta and North Georgia Railway arrived in Pickens County, allowing Georgia marble to be shipped far and wide. One of the first applications was the new state capitol, which used native marble for its cornerstone and employed one and a half acres of the stone in its floors, steps, and walls. Pickens County quarries still produce marble; the county also hosts an annual Georgia Marble Festival featuring a parade, quarry tours, entertainment, craft booths, and a Miss Georgia Marble beauty pageant.
Marble forms when limestone, a sedimentary rock, is heated and compressed. Georgia marble formed from Cambrian (488–542 mya) limestone metamorphosed in the Ordovician period (the period immediately following the Cambrian). The metamorphism occurred because of pressures built up during the formation of the Blue Ridge Mountains, when thrust sheets, layers of surface material sheared off by compressive forces, were stacked up at the edge of the proto-American continent.  
Apart from its traditional use as a building and monument stone, marble has a variety of applications in many industries. The purest marble, being almost entirely calcium carbonate, is a component of toothpaste and is used to increase the opacity and brightness of paint and paper. In plastics and rubber manufacturing, pulverized marble lends stiffness and impact strength. Most Georgia marble quarried today is used in powdered form for such industrial applications.
In Georgia, marble is quarried in Pickens County and Chattooga County. Fifteen other U.S. states produce marble, chiefly as crushed stone; their total output in 2006 was 11.8 tons valued at $116 million. In Europe, the largest deposits are in Austria, Scandinavia, and Italy. The Mount Pentelikos quarry region in Greece was for centuries the largest source of marble for buildings and monuments in the eastern Mediterranean. Marble is found all over the world where limestone rocks have been subjected to high temperature and pressure, usually in episodes of mountain building.
Georgia marble is well traveled. It was used for the capitol in Puerto Rico in the 1920s. In New York, it was chosen for the Stock Exchange building in 1903 and the Stock Exchange Annex in 1922. In California, it was used in the Hollywood memorials to Douglas Fairbanks and Cecil B. DeMille. The Alamo Cenotaph in San Antonio, Texas, is carved of Georgia marble. Important monuments of Georgia marble in Washington, DC, include the statue of Abraham Lincoln in the Lincoln Memorial, the Pan American Building, the National Gallery of Art on the National Mall, the Longworth House Office Building, the Folger Shakespeare Library, and the Federal Reserve Board Building. In the 1960s, the east wing of the U.S. Capitol required renovation; Georgia marble was used for the 24 columns in the façade.
Since ancient times, marble has been selected for the most exalted monuments. The Taj Mahal’s glorious mausoleum is made of marble. Marble facing formerly gleamed from the sides of the Great Pyramid of Khufu (Cheops). The Parthenon, the famed ancient Greek temple to Athena, is one of many Mediterranean monuments made of Pentelic marble. In imperial China, the marble boat, actually a marble pavilion on a lake, was a feature of the finest parks of royalty and the wealthy; the best known is on the grounds of the Summer Palace in Beijing.
State Rock
Marble Sample
State Rock
Marble Hillside
State Rock
Lincoln Memorial
State Rock
National Art Gallery,
Washington, DC
State Rock
Federal Reserve Building
Name: Marble
Chemical Formula: CaCO3
Color: White or lightly colored, usually with dark streaks

Author: World Trade Press

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