Detailed information
Dimensions
36 x 146 x 25
mm
Weight
157 g
Locality
Bisbee, Warren District Mule Mts., Cochise County Arizona, USA
Condition
No recorded repairs
Blending mining history and mineralogical artefact, this fascinating post-mining formation of Native Copper from the famous copper mines at Bisbee in Cochise County, Arizona has produced an 'epimorph', or cast after a railroad spike. This is because copper-bearing acidic mine water reacts with metallic iron whereby the metallic copper is precipitated as copper metal, or Native Copper. In this instance an iron railroad spike acted as the host, but in some mines elsewhere in the world this geochemical process was used to extract 'free' metal, simply by heaping waste iron into settling ponds where the copper-rich mine water was diverted. With a smooth, hollow, central core where the 'spike' lay, the Native Copper forms a quite thick layer with a nobbly outer surface. At 14 cm in length this is a quite prominent artefact for display, especially within a case of Bisbee specimens.
