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Typical Minerals PLAGIOCLASE & MAFICS (amphibole) about 50/50Quartz - absent to trace |
Detail Description
In this detail we see the mixed amphibole and translucent, white sodium plagioclase. Some quartz is present (clear, glassy, grayish - as near the top center of the photo) but it is only about 5%. Note that the plagioclase and amphibole are near 50/50, with plagioclase being more abundant. It is this near mix that puts the rock in the diorite range. Orthoclase is absent. |
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| Last Update: 9/29/00 | e-mail: (Fichtels@jmu.edu) |