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Tertiary Volcanic
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near El Modena, CA, Corona Quadrangle, Southern California
Object number: ROC21721
DescriptionVolcanic (grains are < 0.1 mm) igneous rock that is dark grey on a fresh surface. Based on the color of the rock, its mineralogy is likely plagioclase and pyroxene, if it were darker grey-black it would be a basalt, but this shade of grey makes it more likely an andesite.
In Collection(s)