- Mineral Resources
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- Mica deposits of the Blue Ridge in North Carolina
Mica Mine in Avery county, North Carolina, this site also known as Tom Benfield
Benfield (Tom Benfield) mine
Principal periods worked |
1895, 1910, 1943 |
Workings |
6, adits, one at least 120 ft long. All caved. |
Description of muscovite |
Ruby, hard, minor stain. Some books have brown centers, green edges. |
Production |
Moderate sheet |
Shape |
Lenses |
Size |
1-3 T |
Strike |
NW |
Dip |
NE |
Relation to wallrock |
Concordant |
Wallrock |
Interlayered hornblende and biotite gneiss |
Extent of weathering |
Saprolite (15+ ft). |
Remarks |
Pl-P-Q-M pegmatite, medium to coarse grained, accessory garnet. |
Source of information |
USGS, CMC |
Abbreviations
Principal periods worked
WWI |
World War I |
WWII |
World War II |
int |
intermittent |
Production
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 |