Johnston: Amethyst Rockhounding in Providence County, Rhode Island

Public accessBest spot1 mineralProvidence County, Rhode IslandUpdated July 2026

Mineral reported: 1
Elevation: 260 ft
Best months: March to November

The rock cuts and volcanic outcrops in Johnston, near the Route 6 and Interstate 295 corridor, have produced amethyst and clear to smoky quartz from vugs in the underlying felsic bedrock. It is one of the few inland Rhode Island spots where purple quartz can be found in place rather than as a beach pebble. The exposed cuts make it an accessible stop for seeing the state's crystal-bearing geology. Reported finds include amethyst. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

County: Providence County
State: Rhode Island
Nearest road: Belfield Drive
Postcode: 02919
Coordinates: 41.83668, -71.52098

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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: Roadside cuts and outcrops. Collect only loose material from public right-of-way well clear of the travel lanes and guardrails, and never on active highway shoulders or interstate ramps. Adjacent land is private, so surface picking of float that has already weathered out is the safe and legal approach.

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 Johnston

38°J

40°F

47°M

58°A

68°M

77°J

83°J

81°A

74°S

63°O

52°N

43°D

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 83°F in midsummer and 38°F in midwinter, with winter lows near 21°F.

Climate normals: NOAA 1991-2020 monthlies, PROVIDENCE station (9 mi away), adjusted for elevation.

Geology at Johnston

This spot sits on Blackstone Group - quartzite, mapped as quartzite that formed roughly 1000 to 540 million years ago. Metamorphic terrain like this typically carries quartz veins and sweats, and weathered crystals tend to end up in the soils and streams below.

Mapped unit: Blackstone Group - quartzite
Age: 1000–540 Ma (Neoproterozoic)
Rock types: quartzite
Elevation: 260 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.

Rhode Island Geological Survey
Rhode Island DEM park rules
Community submissions reviewed against published agency rules

Found at Johnston

Each name opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Amethyst Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Johnston.

Across the state line from Johnston

Johnston 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.

MiddlesboroughPlymouth County, Massachusetts · 32 mi awayAgate, Chalcedony
UnionNortheastern Connecticut Planning Region, Connecticut · 33 mi awayFeldspar, Moonstone, Cordierite
NorwichSoutheastern Connecticut Planning Region, Connecticut · 35 mi awayCorundum, Sillimanite
New LondonSoutheastern Connecticut Planning Region, Connecticut · 41 mi awayApatite, Spodumene
Bolton Lime QuarryWorcester County, Massachusetts · 42 mi awayScapolite
SterlingWorcester County, Massachusetts · 43 mi awayChalcopyrite, Siderite

Johnston FAQ

Where is Johnston?+

Johnston is in Providence County, Rhode Island, at 41.83668, -71.52098. Nearest road: Belfield Drive.

What rocks and minerals can you find at Johnston?+

Johnston is reported to produce Amethyst.

Is collecting allowed at Johnston?+

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 Johnston?+

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 Johnston?+

The most comfortable months at Johnston are March to November.

How do I get to Johnston?+

Open the directions link to navigate to 41.83668, -71.52098 in Google Maps. The nearest road is Belfield Drive.

More rockhounding in Rhode Island

See all 17 Rhode Island spots →

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