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granophyre
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Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.
(Bed) Rocks and (Flint) Stones
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granophyre

rock
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granophyre, fine-grained igneous rock that is characterized by a porphyritic texture, having large crystals (phenocrysts) that rest in a nonglassy, finely crystalline matrix (groundmass). Granophyre is similar to granite, except for its fine texture and smaller grain size; those granophyres that have quartz and alkali feldspar phenocrysts in a groundmass of quartz, alkali feldspar, and mafic (dark-coloured) minerals resemble rhyolite, while others consist of micropegmatite (q.v.).