Barrett Hill-Spar mine

Mica Mine in Avery county, North Carolina

Barrett Hill Spar mine

Principal periods worked 1950-60
Workings 8 cuts, 50-200
Description of muscovite Green, "A" structure, bent, cracked, small
Production Small sheet, scrap, large feldspar.
Shape Lenses
Size Several 10-50 T, 100-300 L.
Strike NW
Dip Gentle NE
Relation to wallrock Partly concordant
Wallrock Interlayered biotite and hornblende gneiss
Extent of weathering Partly weathered.
Remarks P-Pl-Q-M pegmatite, fine to coarse grained, accessory biotite, garnet.
Source of information USGS

Geographic context


Principal periods worked
WWI World War I
WWII World War II
int intermittent
Small < 500 lb
Moderate 500-10,000 lb
Large > 10,000 lb
Size of pegmatite
D depth
L length
T thickness
avg average
Internal structure
B biotite
F feldspar
M muscovite
P perthite
Pl plagioclase
Q quartz
Source information
CMC Colonial Mica Corporation
DMEA Defense Minerals Exploration Administration
OME Office of Minerals Exploration
USGS U.S. Geological Survey
OF USGS open-file reports and maps