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