Marble is a metamorphic rock that forms when limestone or dolostone is changed by heat and pressure. Its minerals recrystallize into an interlocking texture, usually dominated by calcite or dolomite. The stone can range in color, while veins and streaks often result from mineral impurities or differences in composition during its formation. Marble is distinct from many igneous rocks, such as granite, because it develops through the transformation of pre-existing carbonate rock rather than the cooling of magma.