Plum Bank Beach: Agate & Moonstone Rockhounding in Lower Connecticut River Valley Planning Region, Connecticut
- Minerals reported
- 2
- Elevation
- 10 ft
- Best months
- March to December
Plum Bank Beach is one of Connecticut's more reliable shoreline spots for surface agate and moonstone, tumbled from glacial outwash and concentrated in the beach gravel by Long Island Sound tides. The Laurentide ice sheet left the material as lag deposits, so the best picking follows low tide and storms rather than any bedrock exposure. It is casual beachcombing, not digging: finds run from pea to walnut sized chalcedony and adularescent feldspar. Reported finds include agate, moonstone. Below: coordinates, access notes, nearby spots, and trip-planning links.
Plan your visit
Generally open to casual rockhounding
- State
- Connecticut
- Nearest road
- Plum Bank Road
- Postcode
- 06475
- Coordinates
- 41.26477, -72.39004
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: Public town beach on Plum Bank Road (Route 154). Parking is restricted to Old Saybrook residents with a recreation pass from Memorial Day to Labor Day, so non-residents realistically visit on foot or in the off season. Connecticut's public trust doctrine covers the wet sand below the mean high water line but does not grant an explicit right to remove rocks, so keep collecting to light surface pebbles.
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 Plum Bank Beach
Comfortable months (45 to 90°F highs)
Best months: March to December. Typical highs run 82°F in midsummer and 39°F in midwinter, with winter lows near 25°F.
Climate normals: NOAA 1991-2020 monthlies, ORIENT PT SP station (11 mi away).
Geology at Plum Bank Beach
This spot sits on ground mapped as Unknown - Unmapped. Tough silica like agate and jasper typically survives weathering and collects as float in drainages and gravel.
- Mapped unit
- Unknown - Unmapped
- 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.
Today's weather
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Get the appSources & 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.
- Connecticut Geological Survey
- CT DEEP state land rules
- Community submissions reviewed against published agency rules
Found at Plum Bank Beach
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 Plum Bank Beach.
- Hewitt Gem QuarryLower Connecticut River Valley Planning Region, Connecticut · 14 mi awayBeryl, Aquamarine, Morganite
- CCC PegmatiteLower Connecticut River Valley Planning Region, Connecticut · 15 mi awayAlbite, Beryl, Columbite
- CCC QuarryLower Connecticut River Valley Planning Region, Connecticut · 15 mi awayBeryl, Aquamarine, Microcline
- Gillette QuarryLower Connecticut River Valley Planning Region, Connecticut · 17 mi awayAmazonite, Aquamarine, Beryl
- Guilford & East HavenSouth Central Connecticut Planning Region, Connecticut · 19 mi awayAgate
- Slocum ProspectLower Connecticut River Valley Planning Region, Connecticut · 19 mi awayBeryl, Rose Quartz
- New LondonSoutheastern Connecticut Planning Region, Connecticut · 21 mi awayApatite, Spodumene
- New Haven Traprock QuarrySouth Central Connecticut Planning Region, Connecticut · 22 mi awayAmethyst
Across the state line from Plum Bank Beach
Plum Bank Beach 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.
- WesterlySouth County, Rhode Island · 35 mi awayBeryl
- Long Island South Shore BeachesSuffolk County, New York · 44 mi awayAlmandine Garnet, Quartz, Jasper
- Moosup RiverProvidence County, Rhode Island · 47 mi awayEpidote, Hornblende, Orthoclase
- West GreenwichKent County, Rhode Island · 48 mi awayAmazonite
- NarragansettSouth County, Rhode Island · 52 mi awayBeryl, Quartz
- Jamestown BridgeNewport County, Rhode Island · 55 mi awayStaurolite
Plum Bank Beach FAQ
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