Stouts Creek Rhyolite (VanEast group)
Hand Sample: Hypocrystalline, porphyritic rhyolite. 20% subhedral to anhedral biotite, quartz, and microcline (sanidine) phenocrysts. 80% grey-brown groundmass. Massive.
Thin Section, XPL: 50% subhedral, medium and fine-grained quartz and plagioclase crystals in 50% matrix that contains opaques and quartz among other minerals. Hexagonal inclusion of very-fine-grained, subhedral, well-weathered grains of quartz, biotite, and opaques.
Western Minerals, Inc
Is Part Of
St. Francois Mountains Batholith, Missouri
Purchased from Western Minerals, Inc
Number of Thin Sections