Datolite

specimen number:
2062197

location:
Delaware Mine, Keweenaw Co., Michigan, USA

description:

A classic Michigan specimen with a pinkish solid datolite nodule, this cut and polished on one face to show the interior. In super condition. Nice color on this one.

The Delaware Mine, situated in Keweenaw County on Michigan's Keweenaw Peninsula, is a premier example of a nineteenth-century copper operation exploiting the Conglomerate Lode. Geologically, the mine targeted the Allouez Conglomerate, a sedimentary layer sandwiched between thick basaltic flows of the Portage Lake Volcanics, where native copper acted as a cementing agent between the rounded rhyolite and felsite pebbles. This unique setting produced large, jagged masses of copper alongside delicate crystallized forms within the porous rock. Historically, the site was first worked in 1847 by the Northwest Mining Company, followed by several reorganizations under names such as the Pennsylvania and Delaware Mining Companies. Despite significant investment and the construction of a large stamp mill, the mine struggled with inconsistent ore grades and high operating costs, eventually ceasing commercial production around 1887. Unlike many other abandoned shafts in the district, the Delaware Mine was later preserved and opened as a tourist attraction in the 1970s, allowing visitors to descend into the first level of the workings.

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