Stegall Rhyolite (Middlebrook group)

Title

Stegall Rhyolite (Middlebrook group)

Identifier

SFM-30

Description

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.

Date

1/20/1969

Contributor

Western Minerals, Inc.

Spatial Coverage

St. Francois Mountains Batholith, Missouri- Middlebrook Group

Accrual Method

Purchased from Western Minerals, Inc.

Number of Thin Sections

2

Geolocation