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Nonfoliated Metamorphic Rocks
1) Anthracite coal: Made from carbon (plant remains) - regional metamorphism of bituminous coal. Anthracite is more dense, harder, and a higher quality fuel.
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2) Hornfels: Fine grained product of contact metamorphism.
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3) Quartzite: Fine to coarse grained. Produced by regional or contact metamorphism of silica sandstone. Often difficult to distinguish from limestone or marble. Use the acid test: Limestone and marble will bubble (give off CO2) when in contact with acid. Both rocks are made of the mineral calcite. Quartzite will not react with acid since it is mostly silica (silicon and oxygen).
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4) Marble: From regional or contact metamorphism limestone or dolostone. Both marble and limestone will bubble (give off CO2) in contact with acid because both are made from the same mineral, calcite.
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5) Metaconglomerate: Coarse grain size. Regional or contact metamorphism of conglomerate causing the pebbles or cobbles to become stretched and distorted.
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