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Star Mine, Copper Harbor, Keweenaw Co., Michigan, USA

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Latitude & Longitude (WGS84): 47° 28' North , 87° 53' West
Latitude & Longitude (decimal): 47.4666666667, -87.8833333333

An underground copper mine consisting of four shafts and two adits located southeast of Copper Harbor, or one mile south of the Clark Mine. The Star Copper Company was organized in 1851 nad began producing copper in 1855. Work was suspended in 1859, but resumed in 1864 due to rising copper prices. Prices dropped again in 1865, forcing the mine to close once again. The mine reopened briefly in 1872 and again in 1881 but closed permanently in 1882. The company remained organized in hopes of reopening the mine, but never did. The property was sold around 1908 to Calumet & Hecla Mining Co.
As with Clark Mine, datolite is the main attraction here, and some very nice specimens can still be found on the rock piles. Prehnite and copper can also be found here. Beware however, that the piles are covered with 120+ years of overgrowth, so finding them can be tricky.

Mineral List

Regional Geology

Mesoproterozoic1000 - 1600 MaCopper Harbor Conglomerate

Major:: {conglomerate},Minor:: {sandstone},Incidental:: {lava flow}

Copper Harbor Conglomerate - Red lithic conglomerate and sandstone; mafic to felsic volcanic flows similar to those of the unnamed formation (unit Yu) are interlayered with the sedimentary rocks.

Note: The unnamed formation has since been named the Porcupine Volcanics (Ypv).

Mesoproterozoic1000 - 1600 MaMesoproterozoic volcanic: mafic rocks

Volcanic: mafic rocks

Mesoproterozoic1000 - 1600 MaMesoproterozoic mixed volcanic, volcaniclastic and sedimentary rocks

Mixed volcanic, volcaniclastic and sedimentary rocks

This designation includes Precambrian iron-formation-bearing sedimentary and volcanic sequences, as well as mixed sedimentary and volcanic or volcaniclastic sequences.

References for regional geology:

Data provided by

Garrity, C.P., and Soller, D.R.,. Database of the Geologic Map of North America: adapted from the map by J.C. Reed, Jr. and others (2005). U.S. Geological Survey Data Series 424 .

USGS compilers. State geologic map data. State Maps.

Geological Survey of Canada. Generalized geological map of the world and linked databases. doi:10.4095/195142. Open File 2915d.

4 valid minerals.

The above list 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.


Rocks & Minerals: 58:111.

Clarke, D.H., 1973, Copper Mines of Keweenaw; Star Mining Company, No. 2, 11 pp.

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