Willemite with Franklinite, Calcite

specimen number:
2072276

location:
Franklin, Sussex Co., New Jersey, USA

description:
Classic fluorescent material from this locality, willemite, franklinite, and calcite are present throughout.

The Franklin Mine, located in the Franklin Furnace district of Sussex County, New Jersey, is globally recognized as the "Fluorescent Mineral Capital of the World." Geologically, the deposit is a unique Precambrian stratiform zinc-manganese-iron ore body hosted within the Franklin Marble, where high-grade metamorphism created a mineralogically complex environment containing over 350 different species. The site is most famous for its willemite, a zinc silicate that occurs in a variety of habits but is legendary for its intense, bright neon-green fluorescence under short-wave ultraviolet light. Historically, mining in the area began as early as the 1600s with local iron extraction, but large-scale industrial operations for zinc commenced in the mid-1800s. The New Jersey Zinc Company consolidated the local mines in 1897 and operated the massive underground Franklin Mine until its closure in 1954 due to the exhaustion of the ore body. Despite the cessation of commercial quarrying and mining decades ago, the site remains a vital center for mineralogical research and education, with the Franklin Mineral Museum continuing to preserve the legacy of this one-of-a-kind geological phenomenon.

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