Gneiss is a medium- to coarse-grained rock that can be found in a variety of locations, but its characteristic banding can perhaps best be seen in massive exposed samples, such as those at Stone Mountain, Georgia and Hickory Nut Gorge in North Carolina. The distinctive alternation of dark and light coloration, which is often an indication of differing proportions of constituent minerals, may be oriented parallel to the ground, but can also occur at an angle. Despite their superficial similarity in appearance to schists, gneisses do not exhibit schistosity, splitting in irregular patterns rather than along planes.
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