Where to Find Chalcedony in Nebraska

Nebraska chalcedony shows up in the Pine Ridge country of the northwest and along the Niobrara River drainage. Box Butte and Sioux counties produce "prairie agate," a banded chalcedony with brown and red fortification patterns, eroded from Tertiary lake-bed silica. The Agate Fossil Beds National Monument area is itself closed to collecting, but the surrounding ranch country and Sioux County gravels still yield small chalcedony nodules. The North Platte River gravels in Cheyenne County add tide-tumbled chalcedony float carried from older volcanic sources to the west. Most Nebraska chalcedony is small and concentrates after seasonal rains expose fresh gravel. The most productive ground is in Pine Ridge country (Sioux County), Box Butte County prairie agate, North Platte gravels (Cheyenne County).

Casual hand collection of common rocks and minerals like chalcedony is allowed on most BLM and U.S. Forest Service land in Nebraska, with daily and annual limits set by the local field office. National parks, most state parks, and tribal land are off-limits. Always confirm rules before a trip.

Pine Ridge country (Sioux County) is the standout. Other strong ground includes Box Butte County prairie agate, North Platte gravels (Cheyenne County).