Riegelsville: Jasper & Quartz Rockhounding in Hunterdon County, New Jersey

Public accessBest spot2 mineralsHunterdon County, New JerseyUpdated July 2026

Minerals reported: 2
Elevation: 160 ft
Best months: March to November

The Delaware River gravel bars near Riegelsville carry a rounded mix of jasper, quartz, and chalcedony pebbles washed down from Appalachian and Piedmont bedrock upstream. This reach sits above the head of tide at Trenton, so the riverbed is non-tidal public water reachable from state boat-access points. It is a relaxed spot for surface pebble hunting when the river runs low. Reported finds include jasper, quartz. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

County: Hunterdon County
State: New Jersey
Nearest road: Mount Joy Road
Postcode: 18077
Coordinates: 40.59375, -75.18346

Get directions View on Google Maps

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

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.

Access note: Reach the bars only from a public access point such as the Riegelsville boat launch. Do not cross private riverfront land, much of which is posted. Take small loose surface pebbles by hand only. No digging, dredging, or sluicing: mechanized or bulk removal from a navigable river can trigger state and federal rules.

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.

Best time to visit Riegelsville

39°J

43°F

51°M

63°A

73°M

81°J

86°J

84°A

77°S

66°O

55°N

44°D

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 86°F in midsummer and 39°F in midwinter, with winter lows near 22°F.

Climate normals: NOAA 1991-2020 monthlies, SPRINGTOWN 1 NNE station (5 mi away), adjusted for elevation.

Geology at Riegelsville

This spot sits on Leithsville Formation, mapped as dolostone that formed roughly 540 to 495 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Mapped unit: Leithsville Formation
Age: 540–495 Ma (Early Cambrian to Middle Cambrian)
Rock types: dolostone
Elevation: 160 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.

Today's weather

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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.

New Jersey Geological and Water Survey
Monmouth County Park System, fossil collecting rules
Sterling Hill Mining Museum
Community submissions reviewed against published agency rules

Found at Riegelsville

Each name 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 Riegelsville.

PhillipsburgWarren County, New Jersey · 4 mi awaySerpentine, Soapstone
ClintonHunterdon County, New Jersey · 12 mi awayBraunite
Oxford Furnace mining dumpsWarren County, New Jersey · 16 mi awayMagnetite
Lambertville QuarryHunterdon County, New Jersey · 18 mi awayAxinite, Datolite
Mt. GilboaHunterdon County, New Jersey · 18 mi awayAxinite, Prehnite, Epidote
Goat HillHunterdon County, New Jersey · 21 mi awayPectolite, Stilpnomelane
Belle MountainMercer County, New Jersey · 22 mi awayMalachite, Cuprite, Hornfels
LambertvilleMercer County, New Jersey · 23 mi awayAxinite, Tourmaline

Across the state line from Riegelsville

Riegelsville 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.

EastonNorthampton County, Pennsylvania · 12 mi awayChert, Flint, Apatite
AllentownLehigh County, Pennsylvania · 14 mi awayJasper, Chert
MacungieLehigh County, Pennsylvania · 19 mi awayBlue Corundum, Sapphire
MarlborovilleMontgomery County, Pennsylvania · 21 mi awayRed Jasper, Brown Jasper, Yellow Jasper
KunkeltownMonroe County, Pennsylvania · 22 mi awayQuartz, Azurite
Bucks CountyBucks County, Pennsylvania · 23 mi awayPetrified Wood

Riegelsville FAQ

Where is Riegelsville?+

Riegelsville is in Hunterdon County, New Jersey, at 40.59375, -75.18346. Nearest road: Mount Joy Road.

What rocks and minerals can you find at Riegelsville?+

Riegelsville is reported to produce Jasper, Quartz.

Is collecting allowed at Riegelsville?+

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 Riegelsville?+

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 Riegelsville?+

The most comfortable months at Riegelsville are March to November.

How do I get to Riegelsville?+

Open the directions link to navigate to 40.59375, -75.18346 in Google Maps. The nearest road is Mount Joy Road.

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