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Marble Quarry

Photo: Greek marble quarry
Bulldozers work in a marble quarry in Thásos, Greece. The Earth's heat and pressure alter limestone into marble, which can range in color from black to white. The ancient Greeks recognized marble's durability, using it to build the Parthenon in Athens. Marble, a metamorphic rock, forms when limestone re-crystallizes.
Photograph by CuboImages srl/Alamy

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