spotting Dark-coloured, rounded areas, up to 2 mm in diameter and sometimes larger, found on the surface of slaty cleavage in low-to medium-grade contact metamorphic rocks (see CONTACT METAMORPHISM) of pelitic composition. Many spots are graphite-rich, having formed by metamorphic aggregation from organic material originally disseminated through the starting sedimentary shale. Rocks may also have a spotty appearance when andalusite is beginning to appear in contactmetamorphosed pelites.
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