Jack Rock mine

Mica Mine in Mitchell county, North Carolina

Jack Rock mine

Principal periods worked 1933, 1943
Workings Cut 45 long, 15 deep
Description of muscovite Pale green to light brown, reeved, cracked, stained.
Production Small sheet
Shape Tabular
Size 6-8 T, 45 L
Strike NE
Dip SE
Relation to wallrock Concordant
Wallrock Biotite gneiss
Remarks Pl-Q-M pegmatite; accessory garnet, biotite, sericite.
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