Cryptomelane with Manganite

specimen number:
2062223

location:
Jackson Mine, Negaunee, Marquette Co., Michigan, USA

description:
Black micro crystals of manganite on a quartz rich matrix with micro crystals of cryptomelane. The cryptomelane has been confirmed by analysis. Neat locality example for both species, collected in 1998.

The Jackson mine, situated within the city limits of Negaunee in Marquette County, Michigan, United States, is celebrated as the historic birthplace of the Lake Superior iron ore industry. Geologically, this foundational deposit is hosted within the Paleoproterozoic-age Negaunee Iron Formation, where intense regional deformation and tectonic folding concentrated high-grade, direct-shipping hard iron ores consisting of massive gray magnetite and lustrous specular hematite interbedded with layers of chert and jasper. Historically, the immense ore body was discovered in June 1845 by a prospecting party led by Philo M. Everett, who was guided to the surface outcropping by Marji Gesick, a chief of the local Ojibwe tribe. This monumental discovery led to the immediate organization of the Jackson Mining Company, which initiated the first regular open-pit quarrying and surface trenching operations on the Marquette Iron Range in 1847. The mine expanded into a massive industrial complex utilizing multiple pits and underground drifts, supplying essential raw materials to the first regional blast furnaces and driving the early economic development of the entire Upper Peninsula. Continuous large-scale mining ran for several decades until the exhaustion of easily accessible high-grade hard ore pockets led to the permanent cessation of regular corporate operations in 1924, though minor dump-reclamation and specialized processing work continued sporadically until the mid-twentieth century.

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