Marble is a non-foliated metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is a metamorphic rock formed when sedimentary carbonates, most commonly Limestone or Dolomite rock is exposed to high temperatures and pressures. Marble forms under such conditions because the calcite forming the limestone recrystallizes forming a denser rock consisting of roughly equal granular calcite crystals.
The word “marble” derives from Greek meaning “shining stone” and the verb “to flash, sparkle, gleam”. It is valued for the many colors of swirls and veins found in numerous varieties of marble. The variety of colors exhibited by marble are a consequence of minor amounts of impurities being incorporated with the calcite during metamorphism. They are caused by impurities of clay, silt, sand, iron oxides or chert, which were present in the original limestone.
Marble is granular and medium grained. It is hard, although component minerals are soft. It is generally gritty to touch.
Marble is quarried around the world in large blocks and cut into dimensional stone. Famed marbles are Carrara and Sienna from Italy. Other notable marbles come from Germany, Greece, Ireland, Macedonia, Romania, Russia, Spain, Sweden, and United Kingdom. In the U.S.A., Pitkens County, Georgia provides Creole, Etowah, and Murphy marbles. In Talladega County, Alabama provides Sylacauga marble. In Winchester County, New York provides Tuckahoe marble. In Vermont, the town of Proctor is the center for Vermont marble. In Colorado the town of Marble is the center for Yule marble.
Marble was used on the U.S. Post Office in Athens, GA.
Marble has been used for sculpture since classical times. As a building material it is often used for building facings, paving, and fireplaces. It is also used for work surfaces, gravestones and for ornaments.
In the Dimension Stone industry the term “marble” is used for any crystalline calcitic rock (and some non-calcitic rocks) that are useful as building stones.
Limestone will sometimes be listed and included along with true Marble. For example “Tennessee Marble” is actually an Ordovician Limestone (Holston Formation) and “St. Genevieve Marble” from Missouri is an Oölitic Limestone (Archimedes Formation).
Quartzite. Marble can appear superficially similar to quartzite. However, a metal blade can scratch marble. Quartzite is much harder. Also marble is effervescent when raw or powdered. It will fizz or bubble if you put dilute hydrochloric acid on it. Quartzite will not react with acid.