Quartz Monzonite (Porphyry) #6

3D Model

This is a gray porphyritic rock with phenocrysts of pink K-feldspar up to an inch long. Smaller phenocrysts include plagioclase feldspar, quartz, hornblende, and mica. This sample is from Garfield, Chaffee County, Colorado, USA. The sample is 8.5 cm across.