Silver with Copper

specimen number:
2062193

location:
South Kearsarge Mine, Houghton Co., Michigan, USA

description:
A cluster of native silver crystal 0.6 cm in size across the top of a crudely crystallized native copper. Collected in 1998.

The South Kearsarge Mine, located in Houghton County within the Keweenaw Peninsula of Michigan, was a significant producer of native copper from the Kearsarge Lode. Geologically, the mine exploited an amygdaloidal basalt flow where native copper was deposited within the gas vesicles (amygdules) and as a replacement mineral within the brecciated flow top of the Portage Lake Volcanics. This specific lode was famous for its consistent mineralization and the presence of silver-copper composites known as halfbreeds, as well as exceptionally sharp native copper crystals. Historically, the mine was operated by the Osceola Consolidated Mining Company, with development beginning in the late 1890s and formal production spanning from 1900 until its closure in 1925. The operation consisted of two main shafts that reached depths of over 2,800 feet, contributing millions of pounds of refined copper to the industrial demand of the early 20th century. Today, the mine site is a popular destination for mineral collectors who search the remaining poor rock piles for aesthetic specimens of crystallized copper, epidote, and pumpellyite that characterize this classic Michigan locality.

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