A faint of metallic massive chalcocite with ankerite running across matrix. Good work example for the species and locality. Collected in 1998.The Baltic Mine, located in Houghton County, Michigan, began exploration around 1882, organized under the Baltic Mining Company in 1897, and officially went into production around 1898 before closing down operations in 1931. Geologically, the mine targeted the Baltic Lode, which is a native copper deposit hosted within a steep, northwest-dipping amygdaloidal flow top breccia. The copper mineralization filled permeable voids in pahoehoe and aa lava flow tops via hydrothermal fluids during ancient regional burial and rifting.
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