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ALKALI GRANITE   (detail)

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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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