Stegall Rhyolite (Middlebrook group)
Hand Sample: Porphyritic rhyolite with medium-grained Potassium feldspar phenocrysts in a brown-red groundmass. Weathers to yellow-brown.
Thin Section: Medium-grained subhedral quartz and plagioclase phenocrysts in matrix.
Western Minerals, Inc.
Is Part Of
St. Francois Mountains Batholith, Missouri- Middlebrook Group
Purchased from Western Minerals, Inc.
Number of Thin Sections