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San Marcos Gabbro
Field Collector: Esper Signius Larsen Jr.
Place Collected:Bachelor Mountain near Murrieta, Elsinore Quadrangle, Southern Califorinia
Object number: ROC21755
DescriptionBlack medium-grained (1-5 mm) plutonic igneous rock. Mineral modes given by Larsen (1948) are 47% plagioclase, 34% hornblende, 8% Fe-ore, 6% hypersthene, 5% augite, and trace amounts of quartz.
In Collection(s)