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Finding Thunder Eggs: Best Environments & Locations (USA)

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In the world of rockhounding, there are several exciting rocks to collect, some more than others. Thunder eggs are among the most beautiful rocks, similar to geodes. To find thunder egg specimens in the wild, you must first identify what you are looking for.

Thunder eggs are typically baseball-sized, with large cavities inside; if cut in half, they contain minerals such as quartz, opal, jasper, or agate. Thundereggs can be found in a variety of US states, including Idaho, Oregon, and California. These rocks are commonly found in creeks and hills.

Let’s take a look at how thunder eggs form, where they can be found, and which states in the United States are best for finding them!

Where to Find Thunder Eggs Near Me
Where to Find Thunder Eggs Near Me

If you want to check out the best rock and mineral identification books, you can find them here (Amazon link).

Where to Find Thunder Eggs Near Me (Most Common Environments)

Thundereggs are similar to geodes in many aspects. Although a geode’s cavity is partly filled with minerals, it fills a thunderegg. This is because of how thunder eggs form.

They occur only in volcanic rhyolite ash flows. As the lava cools, the trapped gases or steam form bubbles inside the volcanic rock’s cavity, and the minerals grow around these bubbles.

The best places to find thundereggs in nature are where volcanic rhyolite was present. The process for thundereggs to form takes millions of years. Still, if you study the geology of an area where volcanism was present, you may find thundereggs in creeks, hills, canyons, mountainous areas, and outcrops.

Let’s analyze some of these mediums and see why they are the best for finding thundereggs!

Creeks and Hills

Thunder eggs are typically found in creeks, hills, rivers, and streams. Thousands of years of geologic activity carried them away from their original formations. Rhyolite, the volcanic rock from which they form, is also common in these areas.

Although it is difficult to tell the difference between a thunder egg and a regular rock, slicing one in half with a lapidary saw will reveal whether you have found what you are looking for.

Mountainous Areas

The high elevations of mountainous areas often reveal various exciting rocks and minerals. Thundereggs were often found in such regions, especially if creeks were also present. 


Rocky outcrops bring forth many interesting rocks and minerals from below the ground. You can even find thundereggs in such mediums, but they are rare. It all depends on the state’s past geologic history. In Oregon, for example, you can find thunder eggs in various outcrops.

TIP: Both geodes and thundereggs look like ordinary stones from the outside. Check out the main differences between these two similar rocks in the article below:
The 7 Main Differences Between Geode and ThunderEgg

BTW: Do you want to know more about rock and mineral identification? The books listed below are the best ones you can find on the internet (Amazon links):

Where Can I Find Thunder Eggs in the USA? The Best Locations

Where Can I Find Thunder Eggs in the USA?
Where Can I Find Thunder Eggs in the USA?

Thundereggs are found throughout the world and in many U.S. states. Even if you aren’t located in the states mentioned here, that doesn’t mean you shouldn’t look for thunder eggs in the environments mentioned above, especially if your state has a rich volcanic history in those regions.

Oregon is the best state to find thundereggs in the U.S., where several rock-hounding locations are available for enthusiasts to collect these volcanic rocks at will. The other great states to find thunder eggs in the U.S. include Idaho, Oregon, California, Arizona, Washington, and New Mexico.

OregonJefferson County, Harvey Creek, Whistler Spring
New MexicoLittle Florida Mountains Mining District, Luna County
WashingtonThe Little Naches River Bed, Yakima Town
Where Can I Find Thunder Eggs in the USA?

Even if you have explored the environments where thundereggs are most commonly found in your state and haven’t found any, there is still one last thing you should try. Join a rockhounding club.

These clubs often know the best locations to find just about anything in any state, and it’s also a great way to make some friends.

Let’s explore some of these states and see exactly where you can find those beautiful thunderegg specimens!


Oregon is, without a doubt, the best state in the U.S. to find thunder eggs, and if you are located here, you are fortunate! Oregon is the only state in the U.S. with thunder eggs designated as its official state rock. It occurred in 1965 as a means to stimulate tourism in the area. 

The native Americans of Warm Springs believed that the thunder egg rocks were created by various thunder spirits that lived in the craters of Mount Hood and Mount Jefferson. These areas are all well known for their thunder egg deposits.

Generally, Eastern and Central Oregon are the most well-known and popular areas where thundereggs are located. The top and most productive regions are the Ochoco National Forest, near Prineville and Mandras, and the Succor Creek Canyon in the eastern parts.

Let’s begin our journey starting in North Central Oregon. Here, you can start hunting for thundereggs at Ashwood, the general area. You won’t find just thundereggs, but jasper and agates as well.

You can also find thundereggs at the Priday Agate Beds, but you must pay a small fee to collect them. The general area around Willowdale is worth exploring because you will also find beautiful geodes apart from thundereggs.

If you’re looking for jasper and thundereggs, head to Sunflower Flat and explore the surrounding hillsides and gravels. An area approximately 6.7 miles north of the eastern end of Ochocho Reservoir has previously yielded many thundereggs.

If you are near Harvey Creek, you can also find thundereggs in the general area. The general area around Forked Horn Butte and White Fir Spring are also popular Thunderegg locations. Around White Rock, apart from thundereggs, you can also find opals and agates.

The general area around Whistler Spring and Desolation Canyon is worth exploring for thunder eggs. South Central Oregon also has a couple of great spots to find thundereggs. For example, the general area around Crane Mountain is filled with thundereggs, agates, and jaspers. 

 You will also find thundereggs, opals, and geodes in the west flanks of Hart Mountain at Warner Peak. The southeast regions of Oregon are also famous for finding thunderegg specimens. For example, the entire surface on the eastern side of Steens Mts. is filled with thundereggs and geodes.

Just west of Burns, the broad area, in general, is excellent for finding quartz crystals, geodes, and thundereggs.

Most of Oregon’s hills and creeks are worth exploring to find thundereggs, especially in Crook County. What’s great about this state is that you have plenty of free-to-dig thunderegg sites and even pay-to-dig sites.

TIP: Check out this article for a complete rockhounding guide in Oregon.


Idaho has various interesting volcanic rocks, minerals, crystals, and fossils. Thundereggs are also found in this state. Thundereggs are most commonly found in the state’s southwestern regions.

It would be best to go to Hog Creek, near Weiser. It is the best thunderegg spot in the state, with enthusiasts able to find stunning amethyst thundereggs throughout the region. Geodes and thundereggs can be found in numerous locations throughout Southern Idaho.

Antelope Creek, for example, is a great place to find these stunning rocks. The area surrounding Antelope Creek is vast and full of exciting specimens to collect. If you plan to visit this location, bring a lapidary saw.

TIP: Check out this article for a complete rockhounding guide in Idaho.


California is home to many interesting rocks and minerals, but you can also find thundereggs here. San Bernardino County is the only place where thundereggs were unearthed in this state.

If you visit this county, head to Lead Pipe Spring. Here, on the north side of the hill near Lead Pipe Spring, you can find thundereggs, opals, jasper, and beautiful blue agates. The Black Agate Hills Geode Bed in the southern part of the state also hosts some more thunderegg formations. 

California has other thunderegg spots, but the best way to find them is by joining a rockhounding club or exploring other regions in San Bernardino County.

TIP: Check out this article for a complete rockhounding guide in California.


Arizona is famous for its wulfenite, copper, turquoise, and petrified wood. However, there are some beautiful thunderegg specimens here as well. If you visit Cave Creek, you will quickly realize that it is one of the best rock-hounding destinations in the state.

Thundereggs are not the only rocks and minerals found here; jasper, quartz, agate, and even precious metals are also present. Thundereggs are commonly found on quartz outcrops in this region.

TIP: Check out this article for a complete rockhounding guide in Arizona.

New Mexico

New Mexico is, without a doubt, a prosperous state for rockhounding, and if you can visit this state, there is a great spot where you are guaranteed to find something interesting.

At the Florida Mountains, in southern New Mexico, near the town of Deming, there is the well-known Rockhound State Park.

Here, rockhounds from many regions gather to explore the many wonders they can find easily, including thundereggs, jaspers, geodes, quartz, or perlite. This state park is among the few where the collection is permitted and supported.

TIP: Check out this article for a complete rockhounding guide in New Mexico.


The state of Washington has a couple of Thunderegg collection sites. For example, the Little Naches River bed, located just northwest of the town of Yakima, has plenty of high-density thunderegg sites on public lands. 

This makes collection easier and legal. If you visit the Little Naches River, explore the general area and find beautiful thundereggs specimens among other rocks, minerals, and crystals.

Various thundereggs were also unearthed near First Creek and Green River. At Mt. Baker, you can visit Blue Lake, Rainbow Falls, or Swift Creek to find various Thunderegg specimens. 

At Mt. Higgins, there are even more Thunderegg locations that you can explore. Creek Crossing, K-Jay Bed, and Iron Gate Point are some of the most known. Pine/Milk Creek is also a great location to find thundereggs, as are the Rim Rock or White River general areas. 

TIP: Check out this article for a complete rockhounding guide in Washington.

TIP: Thundereggs form in layers of different types of stone. This geometry makes it likely that the egg will break along the layers rather than along the middle when hit with a chisel. Find out how to cut and polish thunder eggs correctly in the article below:
How to Cut & Polish Thundereggs: Follow These 6 Simple Steps

FAQ About Finding Thunder Eggs

Still did not find the answer to your questions about finding thunder eggs? Find frequently asked questions in the section below:

What Do Thunder Eggs Look Like on the Outside?

Thundereggs are sometimes tricky to spot. They are nodule-like rocks. However, if you observe a white-gray to reddish-brown rock, chances are pretty high that you have found a thunderegg. Now, the last thing to do is cut the rock in half with a lapidary saw and reveal its contents.

How Do You Know If You Found a Thunder Egg?

Thundereggs often have brown-gray exteriors, and they are abnormally round. They are about the size of a baseball but can get larger. If you find a soft-mud-like or clay-like ball, cut it in half. Chances are high that you have found a real thunderegg.

What States Have Thunder Eggs?

Not all U.S. states have thundereggs. Those include states like Idaho, Oregon, California, Arizona, New Mexico, and Washington.

Thundereggs may also be present in other states, but the best way to tell is to join a rockhounding club or explore the environments in which thundereggs are commonly found.

BTW: If you are looking for the best UV light for rockhounding, find out my picks below (Amazon links):


If there is any rock that comes near the beauty of a geode, then it is the thunderegg. In some cases, it even surpasses it.

Some thundereggs have an otherworldly appearance due to their contents, and just like geodes, they vary from one specimen to another. If you want to find thundereggs in nature, get your equipment ready!

You will most likely find one by exploring the abovementioned environments and understanding how thundereggs form. Check out the states and rockhounding areas mentioned above to maximize your chances of finding thundereggs. Happy hunting!

TIP: There is more to rock tumbling than just following manual instructions. Check out the simple and clever tips and tricks for rock tumbling in the article below:
13 Clever Tips & Tricks For Rock Tumbling You Should Know