Franklin

Mindat.org

Sussex County, New Jersey, USA

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Key Information

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  • Franklin, Sussex County, New Jersey, is famous for its fluorescent minerals, with over 300 species identified, including 60+ unique to the area.

  • It’s located 45 miles northwest of New York City, near Ogdensburg, another mineral-rich site.

  • The area features Precambrian Franklin marble and zinc orebodies, formed through metamorphic processes.

  • Mining started in the 18th century for iron, shifted to zinc by the 19th century, and ended in 1954.

  • The Franklin Mineral Museum preserves the mining heritage, offering educational digs.

  • Climate is humid continental, with annual temperatures from 38ºF to 59ºF and significant snowfall.

Geographic Location

Franklin sits in Sussex County, New Jersey, about 45 miles northwest of New York City, in the northeastern U.S. near Pennsylvania and New York borders. It’s close to Ogdensburg, home to the Sterling Hill Mine, making it a key area for mineral enthusiasts.

Minerals and Geology

Franklin is renowned for over 300 minerals, with more than 60 species first discovered here, many fluorescing under UV light. Key minerals include willemite (green glow), franklinite, and calcite (red fluorescence). The geological setting includes Precambrian Franklin marble and zinc orebodies, formed through high-temperature metamorphic processes, offering a rich field for study.

Mining History and Culture

Mining began in the 18th century for iron, but by the 19th century, zinc dominated, with the New Jersey Zinc Company consolidating operations in 1897 until depletion in 1954. This history shaped Franklin’s culture, with diverse immigrant communities. The Franklin Mineral Museum, founded in 1964, offers exhibits and monthly digs, preserving this heritage.

Climate and Ecology

Franklin has a humid continental climate, with annual highs of 59ºF and lows of 38ºF, receiving 47.85 inches of precipitation and 41 inches of snowfall. This supports deciduous forests and typical northeastern wildlife, influencing seasonal collecting activities.

Citations

Wikipedia