Stone Mountain is a quartz monzonite dome monadnock in Stone Mountain, Georgia, United States. At its summit, the elevation is 1,686 feet (514 m) MSL and 825 feet (251 m) above the surrounding area. Stone Mountain is well-known not only for its geology, but also for the enormous bas-relief on its north face, the largest bas-relief in the world. The carving depicts three figures of the Confederate States of America: Stonewall Jackson, Robert E. Lee, and Jefferson Davis. Stone Mountain is more than 5 miles (8.0 km) in circumference at its base, and is surrounded by the Stone Mountain Park. The summit of the mountain can be reached by a walk-up trail on the west side of the mountain only, or by the Skyride aerial tram.Stone Mountain is a pluton, a type of igneous intrusion. Primarily composed of quartz monzonite, the dome of Stone Mountain was formed during the formation of the Blue Ridge Mountains, part of the Appalachian Mountains. It formed as a result of the upwelling of magma from within the Earth's crust. This magma solidified to form granite within the crust five to ten miles below the surface. Stone Mountain granite extends underground 9 miles (14 km) at its longest point into Gwinnett County. Numerous reference books and Georgia literature have dubbed Stone Mountain as “the largest exposed piece of granite in the world". This misnomer is most likely a result of advertisement by granite companies and early park administration. Stone Mountain, though often called a pink granite dome, actually ranges in composition from quartz monzonite to granite and granodiorite. The granite is composed of quartz, plagioclase feldspar, microcline and muscovite, with smaller amounts of biotite and tourmaline. The tourmaline is mostly black in color, and the majority of it exists as optically continuous skeletal crystals, but much larger, euhedral pegmatitic tourmaline crystals can also be found in the mountain's numerous, cross-cutting felsic dikes. Embedded in the granite are xenoliths or pieces of foreign rocks entrained in the magma.
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