Guernsey Platte River: Agate & Chalcedony Rockhounding in Goshen County, Wyoming
- Minerals reported
- 4
- Elevation
- 4,280 ft
- Best months
- March to November
Guernsey Platte River is a mapped rockhounding spot in Goshen County, Wyoming. Reported finds include agate, chalcedony, banded iron formation, jasper. Below: coordinates, access notes, nearby spots, and trip-planning links.
Plan your visit
Generally open to casual rockhounding
- County
- Goshen County
- State
- Wyoming
- Nearest road
- Road 3
- Coordinates
- 42.24746, -104.63111
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.
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 Guernsey Platte River
Comfortable months (45 to 90°F highs)
Best months: March to November. Typical highs run 88°F in midsummer and 41°F in midwinter, with winter lows near 14°F.
Climate normals: NOAA 1991-2020 monthlies, WHALEN DAM (USBR) station (0 mi away).
Geology at Guernsey Platte River
This spot sits on ground mapped as Alluvial deposits that formed within roughly the last 12,000 years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.
- Mapped unit
- Alluvial deposits
- Age
- < 1 Ma (Holocene)
- Elevation
- 4,280 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.
State guidance last verified:
- BLM Wyoming
- Wyoming State Geological Survey
- Fossil Butte National Monument
- Community submissions reviewed against published agency rules
Found at Guernsey Platte River
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 Guernsey Platte River.
- SunrisePlatte County, Wyoming · 7 mi awayArsenopyrite, Barite, Copper
- HartvillePlatte County, Wyoming · 8 mi awayAgate, Moss Agate, Chalcedony
- Jay EmGoshen County, Wyoming · 20 mi awayAgate, Malachite, Onyx
- Rawhide ButtesGoshen County, Wyoming · 25 mi awayAzurite, Bornite, Chalcocite
- Glendo Red HillsPlatte County, Wyoming · 28 mi awayBanded Iron Formation
- Cooney HillsPlatte County, Wyoming · 31 mi awayGarnet
- WheatlandPlatte County, Wyoming · 32 mi awayMoonstone, Labradorite
- Chugwater CreekLaramie County, Wyoming · 50 mi awayBloodstone
Across the state line from Guernsey Platte River
Guernsey Platte River is close enough to the Wyoming border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.
- Agate Fossil BedsSioux County, Nebraska · 48 mi awayAgate, Jasper, Chalcedony
- Scottsbluff BadlandsScotts Bluff County, Nebraska · 55 mi awayFossil
- Sioux CountySioux County, Nebraska · 58 mi awayChalcedony, Celestite, Fossil
- MontroseSioux County, Nebraska · 65 mi awayAgate, Jasper, Fossil
- Little BadlandsSioux County, Nebraska · 68 mi awayVertebrate Fossil
- Crawford (jasper area)Dawes County, Nebraska · 69 mi awayFairburn Agate, Jasper, Petrified Wood
Guernsey Platte River FAQ
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