Franklinite with Zincite

specimen number:
2102321

location:
Sterling Hill Mine, Ogdensburg, New Jersey, USA

description:
Semi lustrous crystals of franklinite measuring to 1.7 cm in size on a massive deep red zincite matrix. In good condition for one of these classic New Jersey specimens.

The Sterling Hill mine, situated within Ogdensburg in Sussex County, New Jersey, United States, is a world-famous mineral locality celebrated for producing spectacular zinc ores and an unparalleled diversity of brightly fluorescent minerals, most notably rich combinations of willemite, franklinite, and zincite. Geologically, this unique deposit consists of a massively deformed, hook-shaped stratiform ore body hosted within the Precambrian-age Franklin Marble formation, which underwent intense, high-grade granulite-facies metamorphism roughly one billion years ago during the Grenville orogeny. This intense heat and pressure recrystallized ancient zinc and manganese-rich sediments into a unique, iron-depleted mineral assemblage, resulting in open structural textures and distinctive granular matrices that fluoresce in brilliant neon greens and bright reds under shortwave ultraviolet light. Historically, small-scale surface quarrying and localized mining began during the colonial era in the mid-eighteenth century, but large-scale, highly organized underground industrial shaft operations did not fully materialize until the consolidation of property rights by the New Jersey Zinc Company in 1897. Deep underground mining via the main West Shaft ran continuously for nearly a century, supplying critical zinc metal to global markets, until high corporate taxes, declining ore reserves, and severe water-management costs forced the permanent cessation of all commercial extraction operations in March 1986. Through 2026, the underground workings are preserved as the Sterling Hill Mining Museum, serving as an important educational landmark where historic specimens collected during its long operational life remain highly prized, globally recognized benchmarks of American mineralogy.

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