Marble
Marble is a rock resulting from metamorphism of sedimentary carbonate
rocks, most commonly limestone or dolomite rock. Metamorphism causes variable
recrystallization of the original carbonate mineral grains.
The resulting marble rock is typically composed of an interlocking mosaic
of carbonate crystals. Primary sedimentary textures and structures of the
original carbonate rock have typically been modified or destroyed.
Pure white marble is the result of metamorphism of a very pure limestone
or dolomite. The characteristic swirls and veins of many colored marble
varieties are usually due to various mineral impurities such as clay, silt,
sand, iron oxides, or chert which were originally present in the limestone.
Green coloration is often due to serpentine resulting from high magnesium
limestone or dolostone with silica impurities. These various impurities have
been mobilized and recrystallized by the intense pressure and heat of the
metamorphism.
