Pegmatite |
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 PegmatiteIntrusive igneous rock of felsic composition.This is the most common type of pegmatite in the Peninusular Ranges of Southern California. This sample consists of quartz, plagioclase feldspar and both common micas: muscavite (silver) and biotite (black). Sawtooth Mountains, eastern San Diego County. |
| https://gotbooks.miracosta.edu/rocks/igneous/X.html | 2/2/2021 |