Dolomite with Hematite

specimen number:
2062168

location:
Walpole Mine, Dickinson Co., Michigan, USA

description:
Colorless rhombohedral crystals of dolomite averaging 0.3 cm in size across the top of a hematite matrix. In good condition, nice locality example for the species. Collected in the year 2000.

The Walpole Mine, located in Iron Mountain within Dickinson County, Michigan, was a notable producer of iron ore within the Menominee Iron Range. Geologically, the mine targeted the Vulcan Iron Formation, where tectonic activity and hydrothermal leaching created high-grade hematite deposits within folded sedimentary strata. The ore bodies were found in deep troughs of the underlying Quinnesec Formation, often requiring complex underground engineering to extract the soft, blue-toned hematite typical of the district. Historically, the Walpole was opened in 1887 and operated as an independent entity before eventually being absorbed into the larger Chapin Mine complex, which was one of the most productive iron mines in the world. Its primary period of activity occurred between 1887 and the early 1900s, contributing significantly to the industrial output of the region during the peak of the American steel expansion. Today, the site is recognized for its historical role in the development of Iron Mountain and as a classic locality for the study of Lake Superior-type iron formations.

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