Crystal Mountain pegmatites

Region West, Rocky Mountains
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Outline of pegmatite mines and occurrences included in the Crystal Mountain mining district, which encompasses a few dozen historically productive beryl mines. Proterozoic-age pegmatites may not associated with Climax-type deposits.
Identified resources Identified resources of beryllium (beryl). Historical production of beryllium (beryl), mica, and uranium.
Production The Hyatt mine produced 34 tons of beryl, The Wisdom Ranch mine produced ~ 15 t of beryl, and the Buckhorn Mica mine produced about ~2 t beryl and 180 tons of ground mica (Hanley and others, 1950). Byproduct U production at Hide Above lode (~ 0.045 equivalent U3O8) and various others.
Status Past mining.
Estimated resources Estimated resource of 1,100 to 2,100 t beryl (0.02 to 0.08 wt.% BeO) at Hyatt Ranch mine. Buckhorn Mica mine contains 250 to 500 t beryl (Hanley and others, 1950). The authors note potential for larger resources due to abundance of finer grained beryl.
Geologic maps Thurston (1955), scale 1:6,000; Braddock and LaFountain (1988), scale 1:24,000; Braddock and others (1989), scale 1:24,000; Braddock and others (1970), scale 1:24,000; Bucknam and Braddock (1989), scale 1:24,000; Braddock (1988), scale 1:24,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Pegmatites intruding quartz-mica schists of the Idaho Springs Formation, Longs Peak batholith.
Deposits Hyatt Ranch mine (MRDS dep_id: 10013857), Double Opening mine, Buckhorn Mica mine, Wisdom Ranch prospect, Silica Beryl mine, Hide Above lode, Glen O. Barrett, Primrose Beryl lode.
Evidence from mineral occurrences MRDS; Hanley and others (1950).
Geochemical evidence Available sample data are sparse: indicate historical ore grade from 0.02 to 0.07 wt.% BeO. Modal beryl potentially as high as 10% from Wisdom Ranch prospect.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments Proterozoic-age pegmatites. Some critical commodities are inferred from mineral system/deposit type table (Hofstra and Kreiner, 2020).
Cover thickness and description Pegmatite exposed at the surface.
Authors Ryan D. Taylor, Jane M. Hammarstrom, Joshua M. Rosera, V.J.S. (Tien) Grauch.
New data needs Geochemical sampling.
Geologic mapping and modeling needs Unnecessary as entire district covered by 1:24,000 scale geologic maps of Braddock and others (1970; 1989).
Geophysical survey and modeling needs High resolution Rank 1 aeromagnetic and aeroradiometric survey may not work well with this deposit type, except if help is needed in geologic mapping of different petrologic characteristics.
Digital elevation data needs Needs lidar coverage.