Quartzite

Purple to light gray, fine- to medium-grained massive quartzite that contains sparse floating pebbles of quartz interbedded with and grading downward into fine- to coarse-grained feldspathic quartzite with abundant mud chips, trough and planar crossbeds, and flat laminations.
State Montana
Name Quartzite
Geologic age Cambrian, late Proterozoic, or Middle Proterozoic
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Quartzite
References

Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.

NGMDB product
Counties Beaverhead - Deer Lodge - Silver Bow