Centennial Mine, Houghton County, Michigan, USA

This is a piece of the famous Calumet Conglomerate which has been coated in a thick layer of nonyellowing urethane. The Calumet Conglomerate is composed of basalt cobbles which have been cemented together with a red Quartzite which has been replaced in places with Copper. This type of ore constituted the largest single source of Copper in the Michigan Copper district. Shafts were dug as deep as 6000 feet to extract this ore. There were 7 shafts at the Centennial Mine from which 37 million pounds of refined Copper were produced. Examples of this ore are today becoming scarce. The specimen has only been coated on one side.

16.7 x 6 x 0.7 cm

Sold Specimen retained as part of the Minerals Sold But Not Forgotten Galleries