Pyrite pseudomorphs after marcasite with minor sphalerite and galena overgrowths

Abstract

Cluster of intergrown (former) marcasite crystals that have been replaced by pyrite. Some surfaces have minor overgrowths of galena and sphalerite. This mineral specimen is from the Eagle mine, Gilman mining district, Eagle County, Colorado.

For more information about the Minerals of Gilman, Colorado and the collection, see: http://libguides.mines.edu/GeologyMuseum/digitalcollectionsGilman.