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Hornblende Norite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Escondido, CA, San Luis Rey Quadrangle, California
Object number: ROC21754
DescriptionBlack medium-grained (1-5 mm) plutonic igneous rock. Mineral modes given by Larsen (1948) are 61% plagioclase, 12% hornblende, 10% augite, 8% Fe-ore, 8% hypersthene (orthopyroxene, 1% biotite, and 1% quartz. The major minerals are roughly equigranular ~1-2 mm, and black, plagioclase is transluscent and tabular.
In Collection(s)