Sterling Hill in Ogdensburg, New Jersey, evolved from a colonial-era mine first worked in the 1630s under the mistaken belief it held copper into the state's last operating underground mine before closing in 1986. Consolidated under the New Jersey Zinc Company in 1897, the property later became a museum and was added to the National Register of Historic Places for its industrial significance. It is renowned for exceptional mineral diversity, with more than 360 identified minerals, including 35 found nowhere else, and for its striking fluorescent minerals. Extensive underground workings and exhibits above and below ground connect centuries of mining history with notable geology.