3M Quarry: Quartz & Agate Rockhounding in Somerset County, New Jersey

Updated June 2026

3M Quarry is a mapped rockhounding spot in Somerset County, New Jersey. Reported finds include quartz, agate, jasper. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Somerset County
State: New Jersey
Nearest road: Ridge Trail
Coordinates: 40.45828, -74.71350

Geology at 3M Quarry

This spot sits on Diabase, mapped as plutonic that formed roughly 200 to 145 million years ago. Plutonic rock like this weathers slowly into grus and boulders, and the most productive collecting is typically in weathered zones and drainages.

Mapped unit: Diabase
Age: 200–145 Ma (Jurassic)
Rock types: plutonic
Elevation: 380 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 3M Quarry

Best months: March to November. Typical highs run 85°F in midsummer and 38°F in midwinter, with winter lows near 21°F.

Climate normals: NOAA 1991-2020 monthlies, WERTSVILLE 4 NE station (3 mi away).

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 3M Quarry

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 3M Quarry.

Across the state line from 3M Quarry

3M Quarry 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.

3M Quarry FAQ

Where is 3M Quarry?+

3M Quarry is in Somerset County, New Jersey, at 40.45828, -74.71350. Nearest road: Ridge Trail.

What rocks and minerals can you find at 3M Quarry?+

3M Quarry is reported to produce Quartz, Agate, Jasper.

Is collecting allowed at 3M Quarry?+

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 3M Quarry?+

Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.

When is the best time to visit 3M Quarry?+

The most comfortable months at 3M Quarry are March to November.

How do I get to 3M Quarry?+

Open the directions link to navigate to 40.45828, -74.71350 in Google Maps. The nearest road is Ridge Trail.

More rockhounding in New Jersey

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Open 3M Quarry on the map

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