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La Sierra Tonalite
Field Collector: Esper Signius Larsen Jr.
Place Collected:La Sierra near Corona, Corona Quadrangle, Southern California
Object number: ROC21706
DescriptionPorphyritic igneous rock with 70% blue grey prismatic plagiocalse phenocrysts (≤ 7 mm), 20% light grey quartz groundmass (<1mm), 7% black biotite groundmass (<1 mm), and 3% black hornblende groundmass (< 1 mm). This rock isn't obviously porphyritic because it is very monotone.
In Collection(s)