Freibergite with Pyrite - Eagle Mine, Gilman, Colorado, USA

An attractive freibergite with pyrite specimen from the historic Eagle Mine in Gilman, Colorado, USA. The piece features abundant metallic mineralization, with steel-gray to dark metallic freibergite accompanied by contrasting brassy-gold pyrite. Other species may be present.

The densely intergrown crystals create a highly textured, sparkling surface, with numerous reflective crystal faces visible across the specimen. The contrasting metallic tones and complex crystal coverage make this an interesting example from a classic Colorado mining locality.

Freibergite is a complex mineral containing silver, copper, iron, antimony and arsenic, first identified in Freiberg, Germany. According to Mindat.org, there has been recent considerable discussion on whether the species is a valid mineral or part of several different solid solution series with tetrahedrite and tennantite. So for those who are quite particular about IMA mineral names, Mindat recommends labelling specimens "Freibergite Subgroup" of the Tetrahedrite Group.

The specimen comes from the estate of the late Mike Clark who was born and raised in Colorado and later moved to Calgary, Canada. Mike obtained the specimen from The Rock Hut, Leadville, Colorado evidenced by the older label accompanying the specimen. I would estimate the specimen was acquired by Mike prior to 1990.

Minerals: Freibergite, Pyrite
Locality: Eagle Mine, Gilman, Colorado, USA
Crystal System: Cubic (Isometric)
Mineral Class: Sulfosalt
Provenance: Ex Mike Clark Collection (acquired from The Rock Hut, Leadville, Colorado)
Dimensions: 3 cm x 7 cm x 8 cm