Goethite

specimen number:
2062217

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

description:
Lustrous bladed crystals of goethite to 0.2 cm in size across the top of matrix. In good condition, very choice for the species and locality.

The Kennedy mine, situated near Rabbit Lake and the town of Cuyuna within Crow Wing County, Minnesota, United States, is celebrated as the historic pioneer operation that officially opened the Cuyuna Iron Range. Geologically, this major deposit is hosted within the middle Precambrian-age Trommald Formation of the Animikie Group, where tightly folded, highly deformed metasedimentary strata parallel to the axis of the Lake Superior Syncline contain thick, tabular bodies of cherty iron-formation. Millions of years of regional structural fracturing combined with extensive secondary supergene enrichment allowed descending meteoric fluids to leach away primary silica, creating dense concentrations of merchantable, high-grade brown goethite and red hematite iron ores that were uniquely rich in manganese. Historically, after Cuyler Adams mapped the hidden magnetic anomalies using a dip needle in 1895, he and his business partners enticed the Rogers-Brown Ore Company to begin sinking the first regular underground shaft at the site in June 1907. The highly mechanized property completed its initial rail shipments via the Soo Line Railroad on April 11, 1911, and expanded into a sprawling multi-shaft underground complex that supplied crucial manganese-rich ores to harden American industrial steel during the peak demands of World War I. Continuous underground extraction ran for fourteen years until the rapid post-war development of safer, lower-cost open-pit operations across the region made deep-shaft tunneling economically unfeasible, leading to the permanent cessation of all mining at the Kennedy facility in 1925.

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