A Geoscience Digital Image Library

TitleThin section of rhyolite porphyry
DescriptionRhyolite porphyry in thin section, plain polarized view. Unaltered phenocrysts of sanidine (carlsbad twinning), oligoclase, subordinate quartz (in places corroded) and minor biotite are set in a turbid fine-grained equigranular matrix of quartz potash feldspar, and specks of magnetite and hematite. The plag phenocrysts tend to be agglomerated.
LocationUSA ▹ Colorado ▹ Chaffee
PhotographerDarla Sondrol. 2002-04-02.
CollectionWard’s Collection of Classic North American Rocks #12.
Key wordsrhyolite porphyry, rhyolite, Colorado, thin section
Tech details1.18 MB. Thin section. Nikon FDX-35.
GeoDIL number2551