GEODES! What they are, how they form, and more with geology professor, Shawn Willsey

[@Rachel.4644]

Well, that is fun! I was given a few sliced pieces; now I see how they formed. I appreciate your enthusiasm and teaching, Shawn. 👍🏻❣️

[@music100vid]

To me geodes look prettiest when cut with a rock saw and the cut faces polished. Plus, if you cut down the middle, you'll end up with two beautiful and interesting specimens!

[@dmunkphoto]

Went to that same spot in the 70's with Grandma and my uncle to look for geodes. My brother had the brilliant idea of checking the cut for the highway right across from where this video was taken. It was a new cut at the time (the old highway path is just to the west), and we found enough geodes to make a 4th grade kid about as excited as you can get. 40 years later I stopped there with my kids and collected some geodes in that same spot. Thanks Shawn for bringing back so many memories with your videos and adding really interesting information to go with them.

[@brentlacey4214]

Thanks Professor Shawn. I am a retired geologist and did not know how geodes were formed. From Canada but winter a fair bit in AZ. We absolutely love the drive and geological sites from Montana through Idaho, Utah, and Arizona. Always looking for interesting and unique things to see and do. You are adding a lot of things to our “to experience” list. Thanks

[@glenwarrengeology]

Well we can not know everything.

[@MetastaticMaladies]

Came to watch this video because I watched a video by The Bad Naturalist talking about geodes and said this video was awesome lol

[@MrFmiller]

You added to what I already knew about geodes. They are usually described in passing in geology presentations. You provided much more detail. I passed it on to my sons in Idaho. Thanks.

[@glendaglass7264]

Thank you for posting this! When I was a kid in the 1960’s my family and I used to go there on weekends and get geodes. There’s also good quality red and black obsidian close by. Very interesting area.

[@Mchelle021]

I can recall, as a child, coming across geodes as a fun activity item in shops; I guess they can still be found in rock shops. So interesting and more meaningful to see them in context. Love to see your notebook/clipboard show up in the wild. I appreciate how you use traditional and technological depictions very sensibly, Shawn. You are such an effective instructor.

[@oldtop4682]

When I was a kid in No. Utah there was a place I could grab calcite and mica geodes about 10 miles from our house. You had to know where to look, and the outcropping wasn't very expansive. The calcite versions aren't prized much by rock hounds, but are a pretty cool display item. These generally weren't perfectly round as they formed a bit differently, but I liked them.

[@shawnwillsey]

You can support my field videos by going here. Thanks! www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8

[@sharonseal9150]

Interesting! I recall as a child going to Red Top mountain on Teanaway Ridge in Washington to hunt for geodes more than 60 years ago. I was pretty young, but my recollection is that we were searching for geodes containing the unique Ellensburg Blue agate. Now after all theses years I have some context to know more about how they formed. Thank you for this series on types of rocks!

[@michaelmckeag960]

Red Top Mountain, that brings back memories. That mountain figured in my transition from rock hound to mountain climber. The cusp must have been the summer of 1960. The destination in a prior visit to dig geodes became my first summit, in the company of two elderly members of the Seattle Mountaineers. I turned 14 that November, now old enough to enroll in the Mountaineers’ basic climbing course. I see that now there is a road almost to the summit. Back then we hiked in from Mineral Springs CG, at least that’s my sketchy memory.

[@loisrossi841]

Old school rocks! Thank you.

[@ROBERTGOTSCHALL-j8u]

I once visited Crystal Ball Cave. It was on a dirt road a few miles north of Baker, Nevada near the Utah border. It was a giant hollow geode with walls of feldspar that fluoresced in the dark. That was all old Yellowstone stuff, huh?

[@j.c.linden]

These geodes are very different than the ones in southern Indiana! The ones in Indiana are in limestone, and the layers are often deformed around the geodes as if they grew in place. They can have pointed quartz inside, be solid or filled with various microcystaline rounded minerals. No wonder western geodes tend to look different than midwestern ones.

[@jackripleymaddiero]

Thanks😊

[@shawnwillsey]

Thank you!

[@muzikhed]

That was a fun video. Nice to know how geodes form. Amazing place. I hope one day I am able to visit Idaho and check out some of these interesting locations Shawn takes us to.

[@LizWCraftAdd1ct]

Always wondered how they formed. Thanks Shawn.

[@mundodaspedraspreciosas]

I learn a lot from your beautiful work with minerals.a hug and success

[@user-wk1mw9nj3i76]

I’m amazed to see so many geodes, still seeming like bubbles rising to the surface of water, except they’re in old lava layers. That’s new info to this midwesterner. Very cool. 😊

[@gsmith9531]

Been collecting them - never knew how they formed. Thank you for all your interesting "field trips". Please come on east and explain NY geology!

[@Danika_Nadzan]

I had no idea this is how geodes formed! I've only seen the larger, pointed crystal, highly colored ones...do they form in a similar way? Your diagrams are always helpful in visualizing the process. Thanks for another great video!

[@noeljohanson1979]

Excellent excellent EXCELLENT!!! I’ve read information on Geodes and most of the time the Etiology is Unknowable or disputed. THANK YOU FOR AN EXCELLENT DISCUSSION. NE Johanson, MD

[@marsharose2301]

Thanks, you have taught me how to recognize a lot f neat rocks! I’m so appreciative of you and your videos!

[@leslyrae6025]

I appreciated the thorough details on geodes. It added a lot to what I knew and makes me excited ti try to find some again and share the experience with my grandchildren. Any tips on areas they may be found up in the northern panhandle?

[@GB-ew8wc]

Thanks i will now spend more time looking along side the road for mineral treasures.

[@MountainFisher]

I found a 120mm (4.5") geode, I won't say where other than New Mexico. No, not Rockhound State Park, but it is a nice place to go camping and rockhounding in the Fall. Anyway I took the geode to a Rock Cutter and Gemologist I'd seen before and who did very good work and was trustworthy. She bought the high quality rock from me for a decent price and I also haggled a beautiful one carat Marquis cut gem for my collection. I have some nice Montana blue Sapphires, NC rubies and aquamarines, Gorgeous green Demantoid Garnets, but only half carat. I have a lot of gemstones from the US that people are surprised come from here.

[@KA7EII]

Shawn, thank you for the excellent explanation of how these geodes formed! My wife and I went to Rabbit Spring yesterday and we found lots of geodes. I also picked up a lot of the broken pieces to run through the rock tumblers. We ordered your books too - should get them next week.

[@shawnwillsey]

Awesome news all around. Enjoy the books!

[@tommycrossman6297]

Great explanation, thank you.

[@NoOne-yt6yf]

Thanks for teaching!

[@bwc1007]

Excellent video- thank you for making it.

[@VegasCyclingFreak]

That was fascinating. If you ever come to Las Vegas area, there is a very interesting place in the NW part of the city with strange inclusions and bands in the rock that might interest you.

[@GaryCBenson007]

Thank you Professor. Old timey rockhound here. I do not know if this is true or not, and I don't know where to find out, but some rockhounds say that the difference between a geode and a thunderegg is that geodes form in basalt flows and thundereggs form in rhyolite flows. If that deposit is the one I think it is, the chalcedony flouresces under blacklight. I know of people who hunt that deposit at night with a UV light.

[@marcialoofboro306]

Thanks, I have a few and was wondering how they formed.

[@lynneallan8637]

WOW, we have been driving by that area for years and never knew. We will certainly explore. We think IMMG should make an overnight trip to have you take us on a little field trip. Keep up the great videos.

[@oscarmedina1303]

Thanks Shawn. Loved the video.

[@Yetibiker67]

Great to see your subscriber list continuing to grow Shawn!!

[@shawnwillsey]

Hey thanks. It has grown a lot this year, especially since May. I still have no clue which videos will be popular. It's been fun to share these cool stories and locations with people and I've got big plans for next year so stay tuned!

[@jimmymcgill2557]

@@shawnwillsey currently up to about 4 hours of watching time so far so you've definitely gained a sub! lol videos are all awesome and easy to understand! now when i have a bad day of rockhounding and haven't found much if not anything at all its still enjoyable because even the boring rocks i would never take i now know what they are, how they came to be etc. thanks to your channel! and i love your passion, you must be a credit to your students! 👏🏻👌🏻⛏

[@doylechalfant5733]

Thank you again for the video

[@shawnwillsey]

My pleasure!

[@georgelaiacona111]

Geodes, and thundereggs, are a favourite. I'd love to find easy to reach places to collect them.

[@shawnwillsey]

Good luck!

[@lisadyck9503]

That was fun. Thanks, Shawn.

[@Helix-ge1ld]

Beautiful geodes!!!

[@muziknurd]

My favorite geode to find/break open has pink opal in it

[@ukaszbadura5670]

Recently I came across geodes formed in limestone. I wonder how much the process differs from those geodes formed in rhyolite… thanks for nice video

[@w4lauppe]

Very informative, thankyou!

[@kevindorland738]

S.E. Iowa, Farmington, Keosaqu, Des Moines River, area is known for massive quantities of geodes. A few houses are constructed from geodes. Am interested in your insight on Iowa geode formation.

[@ericjohnson1811]

This is great! Thank you!

[@chucklearnslithics3751]

Get the exact same thundereggs on the GC side of course. Put a blacklight on your specimens there. They'll likely have some cool greens and oranges too. Phosphoric material of some kind in there?

[@sallyweiner4180]

So cool! Thank you

[@Whateverhasbeenmynameforyears]

Apparently thunder eggs are only volcanic in origin. So you can not have a limestone thunder egg but you can have a geode thunder egg. Geode is just an open interior with crystals that has a crust. This is my understanding. So this video is about thunder egg geodes.

[@ttonysbirds]

Again thank you

[@7inrain]

I have some stones which a friend brought me from the french coast (a bit south of Calais). They don't really look like the geodes you showed in the video. They are also kind of roundish and they have big vesicles in them but those vesicles are not round and more like wormholes. Their walls look like being some kind of Feldspar. The geological layman that I am would classify the stones as igneous. I still don't know how these vesicles formed but your video delivers a possible explanation.

[@hestheMaster]

Go figure in a state right next door to me, Iowa, has a Goede State park. The state rock of Iowa is the geode. Just to the east of the Mississippi River you can also find them here in Illinois. So interesting to see these strange looking rocks (from a Midwesterner's viewpoint )Shawn.

[@bottomup12]

Really amazing!

[@michaelnancyamsden7410]

Good teaching. Subscribed.

[@xcrockery8080]

I've always wanted to know how these were formed, thanks.

[@WildesCollections]

Bubbles ah... Very cool makes sense

[@keithtaylor6069]

On a ranch in new Mexico is a place where there are marble sized rocks everywhere Can’t climb you fall. It looks like bubbles in lava. A lot are fused together in a bluff have you ever seen this

[@NoOne-yt6yf]

Ooh, nailed it at 6:55! I knew it was vesicles! I bet it will get vitrifiied and then there will be mineralized (silicaceous) ground water intrusion. Not bad for a college dropout that's a 48 year old supporting himself off a liquor store job!

[@shawnwillsey]

Awesome. Knowledge is power!

[@MinterJohnson]

Very informative. Since the geodes are formed from contributions of fluids that passing through the rocks, where are the evidences of the channels that enable fluids travelling? Seems like the geodes in the video are isolated.

[@ErrolMiller-ey3lb]

THANKS

[@stephanieparker1250]

That shirt is epic rock nerd. I love it 🤗

[@no-man_baugh]

TWIN FALLS MENTION!!! Not that I live there ever, I just had a bunch of my maternal family there before they all left to escape the Tragic Valley

[@ricklines8755]

Those look pretty similar to geodes from the Dugway geode beds in Utah. My Dugway geodes flouresce a very pretty green under 254 nm UV light. How about those? Sometimes orange and peach shows up as well under 395 nm, but that bright green is always there with those Dugway geodes

[@glitchyentity2117]

So many here in Kentucky.

[@charlessoukup1111]

Ha ha recall as a little kid on our Michigan beach learning about all these rock types ..pumice floats, cool...and then this black shiney glassy stuff, I thought they were calling it "rocksidean".... : )

[@nitahill6951]

Very cool!

[@guywhoisaguy67676]

Very informative video. Got a question,... When the lava is mobile and folds over itself leaving linier and wide spaces to harden instead of gas bubbles from within then begin filling in the same, Are these given the same label of geode or are they labeled something else because some have long and wide nooks and crevices that go from deep to thin sections because they are folds and not bubbles ? I've run across some recently in New England.

[@joaniewillow]

thank you again. Just wondering if the geodes or maybe just the vesicles form at certain depths in the pyroclastic deposits.

[@shawnwillsey]

The vesicles can be at any level of the pyroclastic deposit but tend to be larger and more numerous near the top where there is less pressure of the overlying rock.

[@grumpy3543]

Thanks. I always wondered how they formed. So what caused those giant geodes that you see in rock shops that are like 6 feet long and filled with amethyst crystals?

[@shawnwillsey]

Similar processes but larger voids.

[@JBaads]

There's geode field near Orderville, Utah. The geodes seem much bigger.

[@Gizathecat2]

I have half of a huge geode with big well formed crystals inside. It came from the Midwest.

[@Slickrock72]

How about this theory. Geodes form in pearlite. Pearlite is a chemically altered obsidian, the chemical alteration being superheated liquid water acting as a solvent permeating an obsidian layer that is under hundreds of feet of overlying rock. In your video, that glassy rock the geodes are set in is pearlite. The geodes start as nucleation sites for needle crystals of minerals dissolved out of the obsidian by the superheated water. These crystals grow outward in all directions, hence forming a spherical growth in the altered obsidian. These spherical growths can become quite large. The centers of these spherical growths, called Spherulites, can begin to dissolve forming a cavity that can then be the site of precipitation of silica formations, or just remain solid. The obsidian/pearlite alteration continues to a point where the pearlite is reduced to a buff-colored powdery deposit in which geodes are often found., sometimes very large melon-sized geodes, like the geode deposits discovered in the Succor Creek area, in extreme eastern Oregon back in the early 1950's. I personally have collected black pearlite with various marble-sized round brown spherulites imbedded in it at a site right on the Oregon-Idaho border near Cow Creek. Some of the spherulites are broken in half and the radiating needle crystal structure is clearly delineated.

[@Whateverhasbeenmynameforyears]

I really was hoping this was about the ones that form not in volcanic rocks. There are other videos about the thunder eggs but there is not much on the other kind.

[@EMES365]

Most of the geodesic open are either hollow or have water in them. I'm in the rust belt so I don't know if they formed here or were imported by man.

[@rpug2920]

Shawn what years were you at Weber and NAU? It feels like deja vu as I got geology degrees from the same schools. Great times!

[@shawnwillsey]

Hi there. I graduated with my BS in geology form Weber State in 1997 and my MS in geology from NAU in 2000. Super proud of both schools and what they did for me.

[@rpug2920]

@@shawnwillsey I'm classes of '72 & 74 respectively and what a wonderful time it was. Great people to work with.

[@kellypeters8330]

Very cool

[@Don.Challenger]

And we can see water would flow quite happily through that crumbly (crummy) ground material (that those geodes are formed in) even if subsequent burials heavily compress it.

[@Don.Challenger]

Question: Is the creamy nature of the quartz an indicator of the waters flow rate and the proportion of mineral dissolved into it? I'll boldly say that if the water was charged with many mineral types there would be more color to the geode's innards.

[@shawnwillsey]

The color indicates the impurities within the quartz (when it was in solution). This chalcedony is mainly creamy white to very pale grey and somewhat translucent so the silica-rich fluid was mostly pure.

[@sstimac]

It's only a thunderegg if the chalcedony is surrounded by rhyolite.

[@funkyfresh1013]

why does the chalcedony form in a concentric ring, rather than just at the bottom of the vessicle?

[@morganprimrose9205]

Good question, I’m wondering the same thing

[@shawnwillsey]

The silica-rich groundwater that forms the chalcedony fills the entire vesicle (it is well below the water table). Precipitation of the chalcedony begins on the wall of the vesicle, slowly depositing more material over time.

[@funkyfresh1013]

@@shawnwillsey Thanks for explaining

[@neilalexander2662]

Years ago a neighbor had acquired geodes in Missouri. They had oil in them. That's the only time I have ever heard of that happening. Any comments?

[@shawnwillsey]

I don't know anything about Missouri geodes. Sorry.

[@hime273]

Did you witness your neighbor actually breaking one of the said Geodes, which had oil in them? If so, what kind of oil are we talking about? Was your neighbor perhaps simply bullshitting you, (If you didn't see the oil inside yourself)? Did your neighbor drill a small hole in the Geodes, squirt oil inside, and seal the hole to play a joke? Crude Oil isn't from fossils as we are told to believe, but is from minerals/rock subjected to immense pressures and heat under continental plates, and doesn't make sense that a Geode would in any way meet the criteria to form oil inside. Hence the reason why Crude Oil varries greatly in composition depending on the rock/mineral types in each location of Oil extraction. But we're told to believe that Oil is derived from fossils, and that Weather Modification/ Geoengineering are simply "Conspiracy Theory," so I guess I'm wasting my time.

[@tcidave]

You need a graphic designer with a lecture hall and you'll be the millennial Nick Zentner. This is a great explanation but I ask as an engineer What is the pressure within that geode? Can we calculate it or can we measure it?

[@TH-ui7yr]

Why is it pronounced Kal-sed-ony rather than chal-sed-ony? Thanks for all the great videos

[@stefansauvageonwhat-a-twis1369]

Seems its cause its an older word based on greek, not that uncommon, like character, or christ

[@erickborling1302]

Wear eye protection at least - whenever hammering on rock.

[@JonMW]

Wow. I did not think that that word was pronounced like that.

[@burningchrome70]

Yep, would have totally thought they were some kind of eggs.

[@ToddDoes]

Sell this shirt on your website, time for merch!

[@shawnwillsey]

Here's where you can get it: www.trollart.com/product/ages-of-rock/

[@tick_magnetedschaper5611]

When Nick uses a rock hammer, he yells " Hi Yea!". It seems to work. Hope you find this helpful.

[@DavidMartz-e2d]

A good partial explanation. Bear in mind that it does not explain banded geodes or other unique types. Wanting to have one explanation does not make it so.

[@3xHermes]

👍

[@jjwwqq]

Don’t you mean that your truck is just a geodes throw away?

[@AKUSUXs]

Thanks Shawn! I have some basalt rocks that I would like to understand how they were made. I've got some pics I could send, just let me know if that would be possible. 😁

[@shawnwillsey]

Sure thing. I’ll do my best. Get good pics if possible.

[@charlessoukup1111]

Sir, is it true that Brown County Indiana is a hot spot for the "remarkable" geodes...empty space inside with large crystals formed? Different colors from the type of minerals encased? Cuz your hunting ground is NO WHERE near Indiana!!

[@shawnwillsey]

Sorry but I don't know about geodes in Indiana.

[@zack_120]

Fascinating, ultimate origin of Homo sapiens, infinite varieties of shape, color, texture, composition,... explaining why the universe is infinitely complex - mother nature 😱👍

[@zmavrick]

I was so disappointed. I Live in the Mid-west so ours are formed in Limestone. So the explanation doesn't help me understand how the holes were formed then another unknown to me mineral had to coat the inside of that hole for the crystals to grow on. The explanation was good in his context, but just didn't help me in our locality.

[@shawnwillsey]

I'm not familiar with midwest geodes but likely a similar process. Voids in sedeimentary rock (like limetone) are created by circulating groundwater through the rock. Later, groundwater with different minerals in solution passes through rock and precipitates minerals within the void.

[@zmavrick]

@@shawnwillsey Thanks

[@DrGeorginaCook]

@@shawnwillseyyes similar process for sedimentary - if you are ever in the UK please visit Castleton, near Sheffield/Manchester. Carboniferous limestones with local volcanic activity = geodes and mineralised veins are abundant. Fluorospar is famous here (Blue John) filling both. Also quartz, barite, calcite, pyrite, galena (lead mining historically) in the veins. There are 3+ cave systems you can go into and take a tour. Lots of rocks lying about to play with! Geology heaven!

[@ronjlwhite8058]

Well dang...that was a great vid too. You got a pattern goin and I like it. Dan Hurd has some amazing vid of digging up and cutting all types of cool stones. He has a claim where he gets, what he calls "ocean picture stone". Getting you out there to explain how that happened would be epic!!!

[@johnturner9818]

Interesting.....you wouldn't suspect beautiful geodes in that inviroment, lol

[@vintageguitarz1]

"Sugar or Coffee in your hot tea" !???

[@funkyfresh1013]

i prefer ketchup in mine, personally

[@stevewhalen6973]

Thanks!

[@traycekidd8221]

Thanks!