Pyrolusite
specimen number:
2102385
location:
Taylor Mine, Baraga Co., Michigan, USA
description: The Taylor mine, located near Alberta in Baraga County, Michigan, was a small but geologically notable iron ore operation situated within the western end of the historic Marquette Iron Range. Geologically, the deposit is hosted within the Paleoproterozoic-age Baraga Group, specifically the Michigamme Slate formation, which locally contains structurally deformed lenses of iron-formation and cherty carbonate rocks. The ore body consisted primarily of soft, earthy hematite and dense goethite formed through the secondary supergene enrichment of the primary iron-bearing sediments by downward-percolating meteoric waters along local fault planes. Historically, iron mineralization was discovered at the site in 1880 by the Taylor Iron Company, which rapidly initiated underground shaft development and open-pit quarrying to exploit the near-surface pocket of iron ore. Full-scale commercial extraction commenced in 1881, shipping ore via the Marquette, Houghton and Ontonagon Railroad, but operations faced chronic water-influx problems and a relatively limited ore reserve. Consequently, active corporate mining operations were short-lived, with the mine shutting down permanently in 1883 after producing just over thirty thousand tons of iron ore, and the abandoned workings have since remained dormant, preserved only as a minor historical locality within the Upper Peninsula mining region through 2026.
Lustrous black needle like crystals of pyrolusite across the top of matrix. Classic locality for the species. In good condition for one of these.
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