Marlboroville: Red Jasper & Brown Jasper Rockhounding in Montgomery County, Pennsylvania

Updated June 2026

Marlboroville is a mapped rockhounding spot in Montgomery County, Pennsylvania. Reported finds include red jasper, brown jasper, yellow jasper, sapphire. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Montgomery County
State: Pennsylvania
Nearest road: North Dietz Mill Road
Postcode: 18971
Coordinates: 40.34796, -75.41087

Geology at Marlboroville

This spot sits on Diabase, mapped as basalt that formed roughly 200 to 145 million years ago. Volcanic ground like this is where agate, jasper, and other chalcedony typically form, filling old gas pockets and fracture seams in the flow rock.

Mapped unit: Diabase
Age: 200–145 Ma (Jurassic)
Rock types: basalt
Elevation: 470 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 Marlboroville

Best months: March to November. Typical highs run 84°F in midsummer and 37°F in midwinter, with winter lows near 18°F.

Climate normals: NOAA 1991-2020 monthlies, SELLERSVILLE station (5 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 Marlboroville

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 Marlboroville.

Across the state line from Marlboroville

Marlboroville is close enough to the Pennsylvania border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Marlboroville FAQ

Where is Marlboroville?+

Marlboroville is in Montgomery County, Pennsylvania, at 40.34796, -75.41087. Nearest road: North Dietz Mill Road.

What rocks and minerals can you find at Marlboroville?+

Marlboroville is reported to produce Red Jasper, Brown Jasper, Yellow Jasper, Sapphire.

Is collecting allowed at Marlboroville?+

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 Marlboroville?+

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 Marlboroville?+

The most comfortable months at Marlboroville are March to November.

How do I get to Marlboroville?+

Open the directions link to navigate to 40.34796, -75.41087 in Google Maps. The nearest road is North Dietz Mill Road.

More rockhounding in Pennsylvania

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Open Marlboroville on the map

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