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Cohasset: Jasper & Epidote Rockhounding in Norfolk County, Massachusetts

Updated July 2026

Cohasset's rugged shoreline is one of the classic South Shore localities for jasper and epidote, weathered from the volcanic and intrusive rocks of the Boston-area terrane and rolled smooth in the beach gravels. Red and yellow jasper and pistachio-green epidote are the signature finds, alongside actinolite, albite, and apatite recorded from the town's coast. The rocky pocket beaches concentrate the best material after storms. Reported finds include jasper, epidote. Below: coordinates, access notes, nearby spots, and trip-planning links.

Cohasset photos

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

1 photo

Aerial view of the rocky Cohasset shoreline and harbor, Norfolk County, Massachusetts

Quick details

Access: Public area
County: Norfolk County
State: Massachusetts
Nearest road: Jerusalem Road
Postcode: 02025
Coordinates: 42.26051, -70.81020

Geology at Cohasset

This spot sits on Diorite, mapped as diorite that formed roughly 1000 to 540 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: Diorite
Age: 1000–540 Ma (Neoproterozoic)
Rock types: diorite
Elevation: 10 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 Cohasset

Best months: March to November. Typical highs run 83°F in midsummer and 38°F in midwinter, with winter lows near 22°F.

Climate normals: NOAA 1991-2020 monthlies, HINGHAM station (6 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 Cohasset

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 Cohasset.

Across the state line from Cohasset

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

Cohasset FAQ

Where is Cohasset?+

Cohasset is in Norfolk County, Massachusetts, at 42.26051, -70.81020. Nearest road: Jerusalem Road.

What rocks and minerals can you find at Cohasset?+

Cohasset is reported to produce Jasper, Epidote.

Is collecting allowed at Cohasset?+

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 Cohasset?+

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 Cohasset?+

The most comfortable months at Cohasset are March to November.

How do I get to Cohasset?+

Open the directions link to navigate to 42.26051, -70.81020 in Google Maps. The nearest road is Jerusalem Road.

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