Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Geologists use the term "marble" to refer to metamorphosed limestone. Marble is a rock resulting from metamorphism of sedimentary carbonate rocks. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Pure white marble is the result of metamorphism of a very pure limestone or dolomite protolith. Marble is extensively used as a building material and in many other exterior and interior applications.