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Centennial Mine, Centennial, Houghton Co., Michigan, USA

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Latitude & Longitude (WGS84): 47° 15' 29'' North , 88° 25' 42'' West
Latitude & Longitude (decimal): 47.25833,-88.42861
Other regions containing this locality:Keweenaw Peninsula, Michigan, USA
Köppen climate type:Dfb : Warm-summer humid continental climate

An underground copper mine consisting of 7 incline shafts near the community of Centennial, just north of Calumet. The Schoolcraft Mining Co. was organized in 1863 and worked the Calumet Conglomerate in a small scale operation until it went bankrupt in 1873. In 1876, the Centennial Mining Co. organized on the previously owned Schoolcraft property and worked the Osceola Amygdaloid until 1896, at which time the company re-organized as the Centennial Copper Co. Work was discontinued on the Calumet Conglomerate and the Osceola Amygdaloid and two new incline shafts were driven on the Kearsarge Amygdaloid. In 1923, Calumet and Hecla took control of the mine and operated it until 1931 when it closed. In 1944, shaft #2 was reopened and operated until 1966 when the mine closed for good. Before C&H took control, the Centennial Mine produced approximately 37 million lbs. of refined copper. The mine today offers the collector a wide range of minerals. A visit to #3 or #6 can produce copper "skulls" and an occasional greenstone (Chlorastrolite). Shafts #1 and #2 can yield copper crystals, silver, datolite, and incredible quartz/epidote crystals. A note about #1 and #2, the county owns these piles and uses them for their activities; at last check these piles were almost gone!

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.

Mineral List

Mineral list contains entries from the region specified including sub-localities

24 valid minerals. 3 (TL) - type locality of valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

1000 - 1200 Ma

ID: 3184728
Mesoproterozoic volcanic rocks

Age: Stenian (1000 - 1200 Ma)

Comments: Mid-Continent Rift

Lithology: Bimodal volcanic rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

1000 - 1200 Ma

ID: 2928161
Portage Lake Volcanics

Age: Stenian (1000 - 1200 Ma)

Stratigraphic Name: Portage Lake Volcanics

Description: Lava flows, mostly basalt, andesite and felsite flows and subordinate interflow sedimentary rocks.

Comments: This unit is the same as unit Yp on paper map of Sims (1992). Description is taken from that unit description.

Lithology: Major:{basalt}, Minor:{basaltic andesite}, Incidental:{rhyolite, sandstone mudstone}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

Localities in this Region


This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Rocks & Minerals (1946) 21: 664.
Williams, S.A. (1963) Anthonyite and calumetite, two new minerals from the Michigan Copper District. American Mineralogist: 48: 614-619.
Rocks & Minerals (1983) 58: 109.
Butler, B.S. and Burbank, W.S. (1929) The Copper Deposits of Michigan. U.S. Geological Survey. Professional Paper 144. 238 pp.
Kilpela, T. (1995) The Hard Rock Mining Era in the Copper Country. 89 pp.
Crichton, W. and Müller, H. (2017) Centennialite, CaCu3(OH)6Cl2.nH2O, n = 0.7, a new kapellasite-like species, and a reassessment of calumetite. Mineralogical Magazine: 81: 1105-1124.

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