Goethite

specimen number:
2062257

location:
Manuel Mine, Crow Wing Co., Minnesota, USA

description:
Lustrous botryoidal goethite across matrix. Good locality example for the species. In good condition.

The Manuel mine, located near Crosby in Crow Wing County, Minnesota, was a notable iron mining operation situated within the Cuyuna Iron Range. Geologically, the deposit is hosted within the Paleoproterozoic-age Trommald Formation, a structurally complex iron formation consisting of interbedded chert, carbonate, and silicate layers that underwent intense folding, faulting, and localized secondary enrichment by circulating supergene fluids. This alteration process concentrated the iron minerals into high-grade orebodies composed largely of soft hematite and goethite, often displaying elevated manganese content characteristic of the Cuyuna range orebodies. Historically, exploration and initial shaft sinking at the property began during the early boom years of the range, with organized underground development and regular commercial ore shipments commencing around 1916. The operation was managed by the Cuyuna-Duluth Iron Company and maintained steady production through the high-demand years of World War I, contributing to the regional output of manganiferous iron ore. Commercial extraction at the Manuel mine property was relatively short-lived compared to neighboring open-pit giants, concluding operations in the 1920s as the localized high-grade underground lenses reached economic exhaustion and production shifted entirely toward larger, more cost-effective open-pit properties across the district.

Questions about this specimen?
Send an email or call us: 314-341-1811.