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Rockhounding North Dakota

North Dakota is a good state for rockhounding.



State Rocks, Gemstones, Minerals, Fossils, & Dinosaurs

Rockhounding Tip:  Knowing state rocks, gemstones, minerals, fossils, and dinosaurs often can be very useful information for rockhounders.  Ordinarily, states with significant mineral deposits, valuable gemstones, fossils, or unusual or significant rock occurrences will designate an official state mineral, rock/stone, gemstone, fossil, or dinosaur to promote interest in the state’s natural resources, history, tourism, etc.  Accordingly, such state symbols often are a valuable clue as to potential worthwhile rockhounding opportunities.

North Dakota - Fossil

Teredo Petrified Wood

State Fossil:  Teredo Petrified Wood (1967)
North Dakota designated Teredo petrified wood as its official state fossil in 1967.  The fossilized wood bears the boreholes of shipworms, genus Teredo, hence its name.  Shipworms are actually a type of mollusk (not worms at all) that were the bane of mariners past and still wreak havoc today on wooden boats and dock posts.  During the Paleocene Epoch, about 60 million years ago, North Dakota was partially covered by the last seaway to invade North America, the Cannonball Sea.  The swamps and lowlands bordering this sea – not too different from Florida today – were home to enormous crocodiles and giant predatory birds.  The marine fauna includes bony fish and sharks, crabs, lobsters, snails, and clams.  Trees that washed into the sea were frequently attacked by shipworms before they were fossilized, leaving them riddled with holes.  As the trees in the mineral rich water petrified, some of the wood was replaced by silica and quartz, thereby preserving evidence of the Teredo.  This wood belongs to a variety of species, including bald cypress, ginkgo, redwood, and magnolia trees.  Teredo petrified wood is one of the most common North Dakota fossils and is known almost exclusively from the Cannonball Formation in Morton County, North Dakota.  The best collecting sites are in the south-central portion of the state.


Rockhounding Resources

State-specific rockhounding books (including the books listed here as well as other books), regional rockhounding site guides, and other helpful rockhounding resources are identified - by category - in the Books & Gear section of Gator Girl Rocks with a link to the Gator Girl Rocks Amazon Store where you may easily browse selected resources and securely place an order.  Your order will benefit Charity Rocks!

Geological Survey logo - North Dakota

North Dakota Geological Survey
The North Dakota Geological Survey has information about local rocks and minerals.  In addition, one of the great – and unusual – programs of the North Dakota Geological Survey is its Paleontology Fossil Digs Program.  This program allows members of the public to participate in an expert-led fossil dig.

BLM Logo


U.S. Bureau of Land Management – North Dakota Office

  • June Culp Zeitner, Midwest Gem, Fossil, & Mineral Trails: Prairie States (Rev. ed., May 1998 – first published in 1955). 
  • June Culp Zeitner, Midwest Gem Trails: Field Guide for the Gem Hunter, the Mineral Collector, and the Tourist (3d. Rev. ed., 1964 – originally published in 1956). 
  • Allan W. Eckert, Earth Treasures Vol. 3 - Northwestern Quadrant (1986; reprint in 2000)
  • James Martin Monaco & Jeannette Hathway Monaco, Fee Mining & Rockhounding Adventures in the West (2d ed. 2007)
  • Kathy J. Rygle & Stephen F. Pedersen, Northwest Treasure Hunter's Gem & Mineral Guide (4th ed. 2008).


Museums of Interest to Rockhounders

Museum - Heritage Center

North Dakota Heritage Center (state museum)
State Capitol – Bismarck, North Dakota
The North Dakota Heritage Center houses the state’s fossil, rock, and mineral collections.


Museum - Dickinson Dino Museum

Dakota Dinosaur Museum
Dickinson, North Dakota
The museum is proud of their Triceratops skeleton and skull that is in excellent shape and recent acquisitions include a baby Tyrannosaurus Rex.  Most of the exhibits are real and many of them were found locally.  The museum also has a fluorescent mineral display containing many different types of stones and minerals.  The museum has over 800 different specimens of rocks, seashells, minerals, and invertebrate fossils as well as vertebrate fossils of animals other than dinosaurs.

Museum - Broste Rock Museum

Broste Rock Museum

Broste Rock Museum
Parshall, North Dakota
The museum, constructed of local field stone, exhibits specimens from all over the world including rocks, minerals, fossils, and meteorites.


Places to Visit - Interesting Sites To See

Site - Theo Roosevelt NP - Cannonball Concretions

Cannonball concretions at Theodore Roosevelt National Park

Theodore Roosevelt National Park
Southwestern North Dakota
The Theodore Roosevelt National Park is located in the Badlands.  The park contains numerous fossils (including petrified wood) as well as interesting geologic formations.  The best known petrified forest in North Dakota is found in the South Unit of Theodore Roosevelt National Park.  There, coniferous stumps from two successive forests have eroded out of the Sentinel Butte Formation.  These trees are related to the modern Sequoia; some stumps are up to twelve feet in diameter.  The stumps are still upright in the place where they grew fifty-five million years ago in a coastal floodplain environment.  The stumps were preserved as floods inundated the forest floor, burying the bases of trees; the unburied trunks and branches simply decayed away.


Site - Petrified Log & Stumps at Capitol grounds

North Dakota State Capitol Grounds
Bismarck, North Dakota
An eighty-foot long petrified log and two stumps are displayed on the capitol grounds by the arboretum trail.


Site - Burning Coal Vein

Burning Coal Vein
Northwest of Amidon, North Dakota
The Little Missouri National Grasslands in southwest North Dakota, managed by the United States Forest Service, includes an underground coal seam that caught fire over one hundred years ago.  The coal continues to burn.



Rockhounding Sites for Children & Families

Petrified Wood
Southwestern North Dakota
Petrified wood is fairly common in southwestern North Dakota.  In fact, during construction of Interstate 94 west of Dickinson, a 120-foot-long, petrified "redwood" log six feet in diameter was uncovered.  The specimen was offered to nearby towns as a tourist attraction, but was reburied when no one wanted it.


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