Green Valley Tonalite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Escondido, CA, San Luis Rey Quadrangle, California
Object number: ROC21763
DescriptionSalt-and-pepper plutonic, medium grained (1-5 mm) igneous rock consisting of 48% white plagioclase, 24% light-grey quartz, 12% black biotite, 11% black hornblende, and 3% black augite. Mineral modes are from Larsen (1948).