Gneiss |
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GneissBanded layers of light colored minerals (quartz and feldspar) between layered bands rich in biotite mica.Triassic age? metamorphic basement rock sample from alluvial gravel deposit at base of Sawtooth Mountains, eastern San Diego County, California. |
| https://gotbooks.miracosta.edu/rocks/metamorphic/6.html | 2/2/2021 |