Aplite
“The fine-grained granite vein”
Aplite is a fine-grained, sugary-textured intrusive igneous rock that forms in thin dykes and veins cutting through larger granite bodies. It crystallizes from the last residual melts of a cooling magma chamber, producing a pale, uniform rock composed almost entirely of quartz and feldspar.
quartz, alkali feldspar, plagioclase, muscovite (minor), tourmaline (rare)
Yosemite National Park (California, USA), Dartmoor (England), Cornwall (England), Black Hills (South Dakota, USA)
6-7
Aplite dykes in Yosemite appear as striking white stripes slicing across the gray granite cliffs, some visible from miles away.
Test Your Knowledge
What does the fine-grained, sugary texture of aplite reveal about the conditions during its crystallisation?
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