Stone Mountain is well known for not only its geology, but also the enormous rock relief on its north face, the largest bas-relief in the world. The carving depicts three Confederate figures, Jefferson Davis, Robert E. Lee and Stonewall Jackson, and has been the subject of widespread controversy.
The Stone Mountain pluton continues 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 misconception is most likely a result of misrepresentation 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 largest bas-relief sculpture in the world, the Confederate Memorial Carving depicts three Confederate leaders of the Civil War: President Jefferson Davis and Generals Robert E. Lee and Thomas J. "Stonewall" Jackson (and their favorite horses, "Blackjack", "Traveller", and "Little Sorrel", respectively). The entire carved surface measures 1.57 acres (6,400 m2). The carving of the three men towers 400 feet (120 m) above the ground, measures 76 by 158 feet (23 by 48 m), and is recessed 42 feet (13 m) into the mountain. The deepest point of the carving is at Lee's right elbow, which is 12 feet (3.7 m) to the mountain's surface.
According to wikipedia