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Franklin-Ogdensburg-Sterling Hill mining district: Willemite & Zincite Rockhounding in Sussex County, New Jersey

Updated July 2026

Sterling Hill in Ogdensburg is the twin of the Franklin deposit and the last of the district's zinc mines to close, now preserved as a mining museum. Its Mine Run Dump is open for fee collecting, yielding fluorescent willemite and calcite along with franklinite and zincite from the same Precambrian Franklin Marble ore body. Zincite and franklinite were first described as mineral species from this district. Reported finds include willemite, zincite, calcite, fluorite. Below: coordinates, access notes, nearby spots, and trip-planning links.

Franklin-Ogdensburg-Sterling Hill mining district photos

Public image records connected to this spot or its reported material.

1 photo

Area view of the Sterling Hill Mining Museum, with open-pit mine and conveyor building, in Ogdensburg, Sussex County, New Jersey

Quick details

Access: Public area
County: Sussex County
State: New Jersey
Nearest road: Plant Street
Postcode: 07439
Coordinates: 41.08346, -74.60533

Geology at Franklin-Ogdensburg-Sterling Hill mining district

This spot sits on Franklin Marble, mapped as marble that formed roughly 1600 to 1000 million years ago. Metamorphic terrain like this commonly hosts vein and replacement mineralization, and old workings typically mark the productive zones.

Mapped unit: Franklin Marble
Age: 1600–1000 Ma (Mesoproterozoic)
Rock types: marble
Elevation: 690 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Best time to visit Franklin-Ogdensburg-Sterling Hill mining district

Best months: March to November. Typical highs run 83°F in midsummer and 35°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, SUSSEX AP station (8 mi away), adjusted for elevation.

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Franklin-Ogdensburg-Sterling Hill mining district

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Nearby rockhounding spots

Other rockhounding spots within driving distance of Franklin-Ogdensburg-Sterling Hill mining district.

Across the state line from Franklin-Ogdensburg-Sterling Hill mining district

Franklin-Ogdensburg-Sterling Hill mining district is close enough to the New Jersey border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Franklin-Ogdensburg-Sterling Hill mining district FAQ

Where is Franklin-Ogdensburg-Sterling Hill mining district?+

Franklin-Ogdensburg-Sterling Hill mining district is in Sussex County, New Jersey, at 41.08346, -74.60533. Nearest road: Plant Street.

What rocks and minerals can you find at Franklin-Ogdensburg-Sterling Hill mining district?+

Franklin-Ogdensburg-Sterling Hill mining district is reported to produce Willemite, Zincite, Calcite, Fluorite.

Is collecting allowed at Franklin-Ogdensburg-Sterling Hill mining district?+

Generally open to casual rockhounding. Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Franklin-Ogdensburg-Sterling Hill mining district?+

A rock hammer, gloves, and safety glasses cover old mining-district ground. Stay out of shafts and adits; the best specimens typically come from dump piles.

When is the best time to visit Franklin-Ogdensburg-Sterling Hill mining district?+

The most comfortable months at Franklin-Ogdensburg-Sterling Hill mining district are March to November.

How do I get to Franklin-Ogdensburg-Sterling Hill mining district?+

Open the directions link to navigate to 41.08346, -74.60533 in Google Maps. The nearest road is Plant Street.

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