Title
Rhyolite
Identifier
SFM-31
Description
Hand Sample: Porphyritic rhyolite with medium-grained potassium feldspar and plagioclase feldspar phenocrysts in a dark red-brown matrix. Weathers with an orangish tinge.
Thin Section: Coarse-grained subhedral plagioclase feldspar phenocrysts in matrix. Opaques present.
Date
1/20/1969
Contributor
Western Minerals Inc.
Is Part Of
Spatial Coverage
St. Francois Mountains Batholith, Missouri
Accrual Method
Purchased from Western Minerals, Inc.
Number of Thin Sections
1