Picture of How to Make Crystal Egg Geodes
I love crystals and especially geodes, so how could I pass up the chance to turn some empty egg shells into crystal filled geodes. I saw it here at  Well, I couldn’t resist, so I started gathering supplies and ran into one problem.  Where to get Alum in bulk?  A 1 oz. jar for $4 is just too much for my budget.  I finally found a 1 pound bag at a place called Allyson’s Pantry ( ) here in Utah ($6.00 for the bag). There are other places that have it on line.   I am excited to show you how to make Crystal Egg Geodes, so let’s get started.
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Step 1:

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1 empty (blown) egg shell
Pointed scissors
Paint brush
Alum (6+ Tbs. per color)
2 plastic or glass cups
Easter egg dyes (you choose what type, I paid $.99 for 6 pellets)
1 cup very hot water
2-3 cup size bowl
Rubber type gloves (to keep your hands from being dyed)
Paper towels

Step 2:

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First take your empty egg shell and divide it in to, two pieces, lengthwise.  I took a pair of pointed scissors and started cutting down one side from the hole at one end to the hole at the other end.  The other side just broke in half when I pulled the two sides apart.  Don’t worry about straight edges.  Geodes don’t often have straight edges, so these won’t need straight edges either.  Make sure each egg shell half is clean and dry.

Step 3:

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Squirt a little glue into each shell half

Step 4:

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and use the paint brush to spread the glue all over the inside of the egg shell.  Sprinkle alum crystals (powder) all over the glue.  Let this dry for several hours.  The alum crystals in the glue provide the “seeds” for the crystals to grow on.  “Seeds” are a NEED in all crystal growing situations.

Step 5:

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Lay each shell half in the bottom of its own plastic or glass cup, with the cut/seeded side up.
sophx441 month ago
Hi we are doing this for a science project as well and I was wondering if we wanted to show the different mediums like borax for instance-- am I still soaking them completely and do I include the alum with the other mediums? Thanks!!
craftknowitall (author)  sophx441 month ago
You can if you use exactly the same amount of alum with each other medium. Use the metric system and use a scale to measure it. What is you hypothesis? What are you trying to discover? With that info I would know how to better answer you question. Hope to hear from you soon.
Im in the process of making these eggs but i was also wondering, do you think i can make them in clam or oyster shells? Thanks :)
craftknowitall (author)  callie.keller.31 month ago
Sounds like an experiment to me> Why don't you try and let me know the results. I can think of no good reason why it shouldn't work. Thanks for asking.
hayleybass1 month ago
About how long does this take? I'm doing geodes for a science project and only have a few months so i dont want anything longer than a month to grow. If you could answer back thanks
craftknowitall (author)  hayleybass1 month ago
These crystals take a couple of hours. You can watch them grow. Thanks for asking. By the way what is your hypothesis?
shawz2 months ago

Can you NOT use alum and still make crystals?

craftknowitall (author)  shawz2 months ago
You can make crystals from sugar like found here: or from salt, basically the same as sugar. Thanks for asking
KwartzKitten2 months ago
These would make nice decorations or conversation starters. I wonder what would work besides eggshells?
craftknowitall (author) 5 months ago
You may not get as intense a color with food coloring. You should try it and see. Let me know how it went. Thanks for asking.

can you use food coloring instead of the dye pills?

after the crystals are grown, can you peel off the egg shell?

craftknowitall (author)  heidisatwork6 months ago

I think you would loose the color. The color seems to be in the shell not the crystals themselves. I just tried and every time I peeled a little shell away the crystal came with it. They really stick to the shell. Sorry.


heidisatwork, I think you can, but I just saw this now

craftknowitall (author)  heidisatwork1 year ago

I am sure you can, but I think you will loose the color and I don't know if the crystals will keep the shape of the egg. Should be a great experiment. Thanks for asking.

ninjakid1110 months ago

interesting, but how is it supposed to come out, in the way you showed. And we do not have to break these, neat.

lmaupin1 year ago

I'm in the process of making one of these, but instead of using a real egg, I went out and bought a few of those giant (3 inches deep, 5 inches long) plastic easter eggs with a colored bottom and clear top. I'm hoping to get a giant 'geode' with a clear removable lid for keeping it safe and displaying it!

natarol1 year ago
exelente gracias por tu ayuda!!!!!
craftknowitall (author)  natarol1 year ago

Su bienvenida

hazelle1 year ago

i made this for a school priject and hope get first placed

craftknowitall (author)  hazelle1 year ago

I hope you do too. Good luck, and thanks for commenting!

I seen the finished product on Pinterest when I was first informed of the link. I have searched for this in books,online,etc. SOooooo very happy to find it, I think they are great. Congrs. on a great job.
Congratulations on taking First Place in the egg challenge. Very cool project that I will for sure try.
craftknowitall (author)  Jason Bedard2 years ago
Thanks, it really surprised me. Lots of fun though.
kkarwan2 years ago
you could also make a deep bowl and just poke the holes and put the alum into the holes to keep the egg whole because then you could crack the egg like a real geode, it'll look like a real egg and you can crack it to the candy inside
craftknowitall (author)  kkarwan2 years ago
Try it and let me know how it goes.
it looks so good
craftknowitall (author)  Reed_Sky_Born2 years ago
Thank you for looking.
Shadow13!2 years ago
Great instructable although your definition of super saturated is not quite correct. When a solution can hold no more medium at the current temperature then it has become fully saturated. A solution is super saturated when the solution is fully saturated at a higher temperature and then allowed to cool. This then allows the solution to hold more medium then if it had just been saturated. This is super saturated.
craftknowitall (author)  Shadow13!2 years ago
I stand corrected, Thank you for commenting and looking.
h88643 years ago
i found that alum crystals make a great antipersperant
craftknowitall (author)  h88642 years ago
Yes it does! Thanks for looking.
These are so neat looking! This would be so fun to do with kids - though they might need to learn patience. :D
craftknowitall (author)  jessyratfink3 years ago
The patience results from making sugar crystals at a 1 week wait. Thanks for looking and commenting.