Frondel, Clifford, 1907-2005-10-062005-10-061936http://hdl.handle.net/2246/21456 p. : ill. ; 24 cm.Includes bibliographical references (p. 5-6).Pyrite, French Creek, Chester County, Pennsylvania -- Smoky quartz, El Paso County, Colorado.1722922 bytesapplication/pdfen-USQL1 .A436 no.829, 1936Dislocations in crystals.Pyrites -- Pennsylvania -- Chester County.Quartz -- Colorado -- El Paso County.Crystal growth -- Pennsylvania -- Chester County.Crystal growth -- Colorado -- El Paso County.Minerals -- Pennsylvania -- Chester County.Minerals -- Colorado -- El Paso County.Crystallography.text