2007-03-02

geodes: how do I open them?

Opening geodes is always a lot of fun. You never know what is inside until it is open, therefore, in order to get the most enjoyment out of your geodes, you have to crack them open. There are a few ways to do that:

[01] Professional geode crackers use a set of two hardened steel points fastened to a power press, which allows you to apply pressure on the geode from two points at the same time. This is a great way to open a geode, but it is a little bit expensive.

[02] The method I prefer to use is a plumber's pipe-cutting tool. These can be found for sale on the internet and through plumbing supply houses. To open a geode using this method: find the most logical fissure or wrinkle along the outside of the geode; lock the geode in the plumber's tool and apply slow, even pressure to the handle. The geode will almost always open with a nice, even crack (no jaggies).

[03] One method is to score the geode all the way around rather deeply with a trim saw. Do this by raising the splashguard and rotating the geode by hand until it is cut all the way around. Now you can use a screwdriver to pry the two sections of the geode apart.

[04] The most common method is to lay the geode in a soft (earth) depression. Look the geode over for any cracks, weak spots, or lines that look like they might be good places to crack it open. That' where you need to apply pressure. When you have found the ideal spot on the geode, use a medium weight hammer (or rubber mallet) and center punch (NOT A STEEL CHISEL). Put the punch in a spot most likely to keep if from sliding off, and hit it several times; easy at first, then harder. If three or four blows do not open the geode, repeat in other spots until a crack does appear. Then use a screwdriver to pry your geode apart.

No matter what method you use, always use gloves and safety glasses. After you have cracked your geode, put the halves back together and secure them together with tape or rubber bands until you get them home. Never hit geodes with a hammer! Although you have on safety glasses, chips from the geode will fly in all directions, placing everyone around you in danger, and leaving chips of the brokern geode strewn all over the ground. Don't open the geodes in the field . . . take them home or to your shop or to someone who can open them for you . . . and leave the property from which you collected the geodes in just as good or better condition than it was when you arrived.

If you have additional information about geodes, unique or interesting ways to open them, or information on geode collecting sites, please leave a comment to this post.

46 comments:

Anonymous said...

How do you clean geodes once you have them open?

Mike B said...

After your geodes are open, use extreme caution when you clean them, so you do not destroy the many micro crystals that might be inside. Cleaning the geode with bruch and water will almost always destroy these tiny crystals. If the geode has a lot of brown iron oxide stains inside, then the smaller crystals are probably already gone, and you can safely clean them with a hose and brush. If there is still discoloration inside the geode after you have tried soap and water, soak them in a solution of oxalic acid. As much mud as possible should be carefully removed before soaking in acid. DO NOT ALLOW ACID TO TOUCH YOUR SKIN. USE RUBBER GLOVES. Using a hose and brushing occasionally will help speed up the cleaning process. When they are clean, wash your geodes out with soapy water and rinse them out extremely well. Good luck!

Melissa Johnston said...

Hi Mike. Thanks for the information. We are going to be opening geodes one month in the youth group meeting. Do you know anyone who has a plumber's pipe-cutting tool that we can borrow?
Thanks, Melissa

Mike B said...

I know a couple of people with pipe-cutters. I'll contact you with that info.

Anonymous said...

What if your younger, and the adults you live with don't have any power-tools to open a geo with. What if all you have is a small hammer! Do you have to open them?

argon(one) said...

You can certainly leave a geode unopened and enjoy it without having to crack it open. If you don't have any of the tools listed in the "field guide" and you still want to crack it open, I would suggest that you look it over very closely and try to find a fissure (crack or depression) that looks like it might make a clean break. Cover your geode with an old towel or other piece of cloth. This is to keep fragments of the geode from flying out and hurting you or someone around you. Put on safety goggles. Strike the geode with a hammer just hard enough to crack it open. Don't pound it really hard or you will have hundreds of little pieces . . . not good! It may take several strikes to crack your geode, but it will eventually crack open.

Anonymous said...

Sorry, I made a mastake. I was meening to say, "Do you now how to open the geo without facturing the crystal that much? Thank you!

argon(one) said...

When you crack a geode using a hammer there is always a possibity that you will damage the crystals. Check in your neighborhood to see if there might be a neighbor or relative with a center punch and a mallet that might be willing to help you open your geode.

If you happen to live in the Memphis area, you can come to one of the Memphis Archaeological and Geological Society's meetings or email one of the members to get assistance with your geode. The web address for the Memphis club is www.memphisgeology.org . . . or check in your part of the country for a gem and mineral society that might be able to help you.

Anonymous said...

After I have cleaned out my geode, how do I polish it and make it really shine? Thanks!

argon(one) said...

Prior to opening your geode, you could place it in a rock tumbler for a few days, if you have a tumbler large enough to accomodate it. If you take your time and properly clean your geode after it is opened, you should not need to enhance it further. Because of the nature of a geode, you risk damaging your crystals or injuring yourself if you try to polish the inside by hand. You can polish the rough edges of the two halves of your geode by using a rotating flat lap (a grinding tool used by lapidary artists). If you do not have a rock tumbler or a flat lap available to you, I would suggest that you contact the gem and mineral club or rock shop closest to you for help.

Anonymous said...

how do I know if the rock i get is a geode? Is there any tests i can run on it before I crack it open to know if its a geode? plz answer, thx!!

argon(one) said...

Compare the weight of a solid rock to the weight of your potential geode. A geode will weigh much less than a solid rock because the inside is hollow. If the inside is not hollow, AND if there are no crystals inside [all pointing toward the center of the geode] then your rock is not a geode. You can also shake your potential geode, while holding it close to your ear. If you hear a rattle [faint or loud] inside, it is a geode. The sound you hear is probably small crystals that have broken loose.

Anonymous said...

i have a solid softball sized geode. i would like help by telling me how to open it without a special saw. what should i do to open but not wreck it?

Josh said...

Hi, i'm a 19 yr old rock and mineral enthusiast. I know a little about rocks and minerals but I need some info. I just found some quartz geodes in my front yard a few days back. Is it alright to cut them open with a floor tile saw, which is a steel disc cooled by water?

argon(one) said...

If the rocks you found are geodes you should not use a saw to open them. Cutting a geode open could damage your saw blade as it cuts through the crystals inside. Try to find a gem and mineral society in your area. There's a possibility that someone in a local gem and mineral society will have a geode cracker. Cracking the geodes open is the best [and safest] way to open your geodes.

Anonymous said...

Can i find any geodes in england?? cos i live in england and i really wanna find some geodes!!! Thx!

Anonymous said...

Is part of a amethyst geode worth alot of money cos i was given part of a amethyst geode and rose quartz but the rose quartz has gold stuff on the end of it. how much id it worth??

10 yr old DarkDecimation said...

I want to find some geodes in Houston Texas and i now their here because my friend found one outside and i thought it was really cool,plz answer my question.

Teresa said...

sorry wrong question i meant were can i find them in Houston Texas like around what moist dirt my backyard were?

argon(one) said...

Hello 10 yr old Dark... You can contact the Houston Gem and Mineral Society for information on geodes in the Houston Area. Their phone number is 281-530-0942; or email the president of that club [Terry Proctor] at president@hgms.org . Good luck!

10 yr old DarkDecimation said...

Thanks!!!!!!!!!!!!!

kim said...

Hi I just found around 200 geodes in our creek. Besides being beautifull are they worth anything? I am not saleing then just want to know. I have always loved geodes ,but I have never opened one,I heard that lowers their value is this true?

argon(one) said...

Your geodes are definitely worth something. The value will depend on what crystals are inside. An average geode [say 4 inches in diameter] can be worth anywhere from $10 to $40 dollars. But you have to crack one of your geodes in order to find out what's inside. Cracking them does not lower the value. Unopened, your geode is worth perhaps $5 to $15 dollars. If you open one, report back and let me know what crystals you find inside. Good luck.

Anonymous said...

When you have a geode and had it cut in half and the inside is solid blue how do you clean and shine it up it looks like a waterfall on one side and a mountain on the other

Anonymous said...

I tried to clean my daughter's older very dusty geode with hot water and now I have a dull looking group of crystals with a whitish cast. Any help for this before she realizes and kills me??

argon(one) said...

Okay... now that you have dull and milky crystals, try soaking them in polident denture cleaner overnight... seriously.

Jeff said...

In regards to some of the posts I saw about "not using a saw"- it is common practice to use a diamond blade wet saw (with proper oil lubricant instead of water) called a 'slab saw' for cutting geodes and other rocks open. As these saws are expensive, an amateur rockhound should look into local rock clubs and organizations for help doing this level of geode opening. If your geode may contain something of value like amethyst or agate, cutting it with a professional saw is the BEST option, as you cut down on the amount of material you lose due to the opening process, cut down your chances of cracking the minerals inside, and showcases your find all at the same time.

You should not clean your geode until you've determined what minerals are inside, since acid will destroy things like iron inclusions, sphalerite, pyrite, calcite, etc. Oxalic acid is good, but muriatic acid (another name for sulfuric acid) is better. Whenever working with acid, use not only proper hand protection, but eye and breathing protection too- or you could suffer permanent, or even fatal,
damage to your eyes and lungs. If you soak a rock for three days in acid, a good rule of thumb is to soak it for equal time in water.

Since saws can be expensive, they're not always the most practical method for opening a geode, but they're certainly available for those willing to put in a good faith effort.

In regards to using a TILE SAW, it can be done, but if the saw motor isn't powerful enough, the blade isn't the correct type of blade, if you're not using the right lubricant, or if you try to cut the rock too quickly, it is a guaranteed way to ruin a good blade and burn up a working motor.

Anonymous said...

Just a note.....regarding Jeff's comment about the acid....Muriatic Acid is NOT Sulfuric Acid!!! It is Hydrochloric Acid...BIG difference in how you should handle. http://en.wikipedia.org/wiki/Muriatic_acid

txredneckcop said...

Hi. Just wanted to know, I was explaining to my sons the fun I had when I searched for geodes with my dad in Kentucky as a kid. I would like to do the same with my sons. I live in San Antonio, TX.
How do I get started and how do I find the nearest place to start looking for geodes? Thanks.
Chad Thatcher

David said...

What type of Geodes can I find in SE Kansas? Also, How long should I let the qeodes dry before trying to open them?

Thanks,

Dave

Anonymous said...

Hi,
I'm new to crystals and just bought an Amethyst Geode. Inside the Amethyst i saw gold yellow lines inside each individual crystal. Is that considered as rutilated quartz. Does it affect the value of the geode.

The salesperson said that with the gold lines it makes the crystal more expensive, especially when the geode has an agate surrounding. pls comment. Thanks

Jen

Anonymous said...

Hi; I live in New Zealand and am interested in finding geodes. Could anyone help me?

Anonymous said...

How can you tell if a rock is a geode without opening it??

AlaskaGirl1 said...

Thanks for all the information! I got some geodes, including 'potato' geodes, while in Nederland, CO in May. Of course I want to open them, and now I know HOW to do it. Will try one of the potato geodes first, since I have two of them. Thanks again!

Anonymous said...

Can you find Geodes in England because i started collecting them and i want to know if i can get some geodes naturally instead of buying them

Anonymous said...

Can you find Geodes in England because i started collecting them and i want to know if i can get some geodes naturally instead of buying them

Becca Medley said...

I live in Lawrenceburg, KY. I think i may have found a geode but I am not sure. Where can I find Geodes in my town or nearby? Is it true that you can find them on farmland, creek beds, and fields? Where else can I find them? Is there a book or a link where I can find out colors, sizes, shapes, locations, and the value of each geode? PLEEEEEEEEEEEEEEEASE help!!! I'm a geode virgin... I guess that's what I would be called.

Thanx, Becca

Anonymous said...

I found several large geodes approximately 25 to 30 inches in diameter. They were so dense that breaking them open with a saw or hitting them was impossible. My little brother put them in a log splitter that applied 20,000 lbs of pressure. We had to leave them in the splitter for several minutes before they eventually broke. One cracked perfectly in half and the another one broke into three pieces, but it worked. I now have beautiful, large geodes to place in my flower garden. It was an unconventional method, but it worked.

Awesomekid4 said...

I live in west bloomfield township and I don't have any woods or creaks or any other of the sort in my backyard. Could you please tell me where a good place to find one is? I know that they are here because someone I know finds them in her backyard. Thanks!

Anonymous said...

I live in southwest,MI and was wondering were to find geodes. Please anwser asap.

Anonymous said...

I leave in ogden ut where is closest place to find geodes :)

Jacob Kane said...

Okay my brother corrects geodes and just cracked one into part night, much to his surprise, he found a solid white substance inside covered with what looked like a rusty iron powder, he rinsed it off and lots of air bubbles came out of the substance, anyway you can shoot me an email and I chasm send you pictures of this to get a better idea of what's inside this geode? Jtk86@Yahoo.com

Firestomper said...

I found a lot of great info. Thank-you
As to sawing a geode in half, we found a large 20"+ and I was wondering is I could open it using my large concrete saw?
Thanks
Kevin

lee said...

Hi i have noticed that a few people have put on here about trying to.find geodes in england and where to find them i also have the same quetion where are you most likely to find them in england please could someone answer this for me thankyou ?????

@AmericanGeode said...

We use a soil pipe cutter, and it's better and more fun for 2 to 3 people to be involved. Surprisingly,,,,we have had great success with Oxy-Clean when we leave the geodes for 3-4 hours in hot water. We have used acid, but Oxy-Clean does a great job, and is safer.

Cat WalkGames said...

hi i live in newport news va and i dont know where i should start looking