East Granby Quarry: Datolite & Aragonite Rockhounding in Capitol Planning Region, Connecticut

Updated June 2026

East Granby Quarry is a mapped rockhounding spot in Capitol Planning Region, Connecticut. Reported finds include datolite, aragonite, calcite, celestine, epidote, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Capitol Planning Region
State: Connecticut
Nearest road: South Main Street
Postcode: 06026
Coordinates: 41.93611, -72.73999

Geology at East Granby Quarry

This spot sits on Holyoke Basalt, mapped as basalt and gabbro that formed roughly 200 to 175 million years ago. Volcanic ground like this weathers into rocky slopes and float, and fresh exposures in cuts and drainages are usually the most productive places to look.

Mapped unit: Holyoke Basalt
Age: 200–175 Ma (Early Jurassic)
Rock types: basalt and gabbro
Elevation: 200 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 East Granby Quarry

Best months: March to November. Typical highs run 85°F in midsummer and 35°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, HARTFORD-BRADLEY INTL AP station (3 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 East Granby Quarry

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 East Granby Quarry.

Across the state line from East Granby Quarry

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

East Granby Quarry FAQ

Where is East Granby Quarry?+

East Granby Quarry is in Capitol Planning Region, Connecticut, at 41.93611, -72.73999. Nearest road: South Main Street.

What rocks and minerals can you find at East Granby Quarry?+

East Granby Quarry is reported to produce Datolite, Aragonite, Calcite, Celestine, Epidote, Fluorite, Galena, Prehnite, Quartz.

Is collecting allowed at East Granby Quarry?+

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 East Granby Quarry?+

A rock hammer, gloves, and safety glasses cover old mining-district ground. Stay out of shafts and adits; the best specimens typically come from dump piles.

When is the best time to visit East Granby Quarry?+

The most comfortable months at East Granby Quarry are March to November.

How do I get to East Granby Quarry?+

Open the directions link to navigate to 41.93611, -72.73999 in Google Maps. The nearest road is South Main Street.

More rockhounding in Connecticut

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Open East Granby Quarry on the map

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