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Typical Minerals QUARTZ > 20% ORTHOCLASE is greater than Plagioclase Mafics - < 10% |
Detail Description
In this detail the pinkish colored orthoclase stands out clearly, but quartz is also common (clear, glassy, no cleavage; for example the grain on the bottom, just left of center.) Mafic (black)minerals are rare (<10%) in granites. The mafic mineral is most likely biotite with a few grains of amphibole too. |
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| Last Update: 9/29/00 | e-mail: (Fichtels@jmu.edu) |