Title
Rhyolite
Identifier
SFM-8
Description
Hand Sample: Holocrystalline fine-to-medium-grained phaneritic rhyolite with quartz, biotite, and plagioclase crystals generally no larger than 2mm. Weathers to brownish-orange.
Thin Section, XPL: 35% medium-grained anhedral quartz and subhedral plagioclase feldspar crystals surrounded by very-fine grained quartz crystals. Small patches of very-fine-grained biotite interspersed. Opaques present.
Date
1/20/1969
Contributor
Western Minerals, Inc.
Is Part Of
Spatial Coverage
St. Francois Mtns. Batholith, Missouri
Temporal Coverage
Undifferentiated Van Erst Group
Accrual Method
Purchased from Western Minerals, Inc.
Number of Thin Sections
1