Manganite with Barite

specimen number:
2062279

location:
Lucy Mine, Marquette Co., Michigan, USA

description:

Lustrous black crystals of manganite across the top of a crystallized barite matrix. In great condition. Classic for the species and locality. The specimen comes with a previous label from the Seaman Mineral Museum at Michigan Tech University as shown at the end of the video.

The Lucy mine, situated within the Negaunee area of the Marquette Iron Range in Marquette County, Michigan, was a historic underground iron ore operation originally known as the McComber mine. Geologically, the deposit is hosted within the Paleoproterozoic Negaunee Iron Formation, a thick sequence of highly deformed banded iron formations consisting of alternating layers of iron oxides and chert. Tectonic fracturing and subsequent hydrothermal alteration enriched specific zones of the formation, concentrated soft, earthy hematite and hard specularite ores within structural troughs and fault blocks. Exploration at the site began in 1870, with the first commercial ore shipments recorded in 1872 under the management of the McComber Iron Company. The property was renamed the Lucy mine in 1887 when it was acquired by the Lucy Mining Company, which expanded operations to include multiple shafts targeting the deep hematite lenses. Industrial extraction at the site continued intermittently through economic cycles until 1912, when the underground reserves were largely exhausted and the mine was permanently closed and dismantled, concluding forty years of active production on the property.

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