A Geoscience Digital Image Library

TitleThin section of phonolite
DescriptionThis is a plain polarized thin section of phonolite. The few phenocrysts are tablets of anorthoclase (“Moire-type” extinction). The trachytic-textured matrix consists of parallel thin orthoclase crystals, stubby nepheline euhedra and aegirine microlites in plumose clusters. Accessories are magnetite, pyrite and analcime.
ChronostratigraphyTertiary (Post-Oligocene)
LocationUSA ▹ Colorado ▹ Teller. Near Cripple Creek. Beacon Hill.
PhotographerDarla Sondrol. 2002-04-08.
CollectionWard’s Collection of Classic North American Rocks #21.
Key wordsphonolite, Colorado, thin section
Tech details1.06 MB. Thin section. Nikon FDX-35.
GeoDIL number2621