Marble

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Rock class:Metamorphic Rock
Composition:Calcite with (usually) graphite, pyrite, limonite, dolomite, quartz, and mica.
Color:Grey, Varies considerably, White
Grain:Crystalline grains larger than in limestone
Environment:Marble can be produced by regional, contact, or dynamic metamorphosis of pure limestone. Marble requires high temperatures (900 degrees C) and moderate pressures (10 Kb) to recrystallize, and is usually formed inside the Earth.
Uses:Material for famous marble sculptures and temples. Marble is used as a building material, either rough or polished. It is sometimes used in the chemical industry.
Comments:Acid rain slowly dissolving exposed ancient structures and artifacts. Marble, heated to great temperatures, decomposes into carbonic acid gas and lime (CaO), which is used as fertilizer and plaster: CaCO3 --> CaO + CO2. [marbles.jpg]