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Diamond Hill Park, Cumberland: Amethyst & Quartz Rockhounding in Providence County, Rhode Island

Updated July 2026

Diamond Hill is a massive white quartz outcrop with a 350-foot vertical face, historically Rhode Island's most famous locality for milky and smoky quartz and the amethyst that gave the hill its name. The state transferred the land to the Town of Cumberland in 1997, and it is now a 373-acre public town park with the quartz ledge as its centerpiece. Loose quartz litters the base of the outcrop, and the hill sits at the center of Cumberland's mineral country near the only known outcrop of cumberlandite, the state rock. Reported finds include amethyst, quartz, smoky quartz. Below: coordinates, access notes, nearby spots, and trip-planning links.

Diamond Hill Park, Cumberland photos

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

1 photo

Diamond Hill Park in Cumberland, Rhode Island, the wooded hill built on a large white quartz outcrop long known for amethyst and quartz.

Quick details

Access: Public area
County: Providence County
State: Rhode Island
Postcode: 02864
Coordinates: 41.97402, -71.34606

Geology at Diamond Hill Park, Cumberland

This spot sits on Pondville Conglomerate, mapped as Pennsylvanian conglomerate and arkose. Sedimentary rock like this erodes unevenly, so the most productive collecting is typically along fresh cuts, badland slopes, and active drainages.

Mapped unit: Pondville Conglomerate
Age: Pennsylvanian
Rock types: conglomerate and arkose
Elevation: 250 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 Diamond Hill Park, Cumberland

Best months: March to November. Typical highs run 84°F in midsummer and 38°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, WOONSOCKET station (8 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 Diamond Hill Park, Cumberland

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 Diamond Hill Park, Cumberland.

Across the state line from Diamond Hill Park, Cumberland

Diamond Hill Park, Cumberland is close enough to the Rhode Island border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Diamond Hill Park, Cumberland FAQ

Where is Diamond Hill Park, Cumberland?+

Diamond Hill Park, Cumberland is in Providence County, Rhode Island, at 41.97402, -71.34606.

What rocks and minerals can you find at Diamond Hill Park, Cumberland?+

Diamond Hill Park, Cumberland is reported to produce Amethyst, Quartz, Smoky Quartz.

Is collecting allowed at Diamond Hill Park, Cumberland?+

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 Diamond Hill Park, Cumberland?+

A rock hammer, a small pry bar, gloves, and safety glasses cover most crystal ground. A screen helps in loose pocket soil, and newspaper protects points on the way out.

When is the best time to visit Diamond Hill Park, Cumberland?+

The most comfortable months at Diamond Hill Park, Cumberland are March to November. Typical highs run 84°F in midsummer and 38°F in midwinter, with winter lows near 19°F.

How do I get to Diamond Hill Park, Cumberland?+

Open the directions link to navigate to 41.97402, -71.34606 in Google Maps. Some spots are remote, so check road conditions before driving out.

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