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Project

Crystal Egg Geodes

Introduction

Geodes can be grown without using egg dye. The resulting crystals are clear to milky white, like quartz. While large chicken eggshells are suggested in this process, larger eggshells can be used. Simply increase the size of the plastic or glass container and double or triple the amounts of dye (1 packet), alum (3/4 part), and water (2 parts) used to create the growing solution.

This Easter craft from Jim "Figgy" Noonan doubles as a science project, offering an opportunity to show kids the crystallization process at work. To make a fluorescent variation for Halloween, substitute the water and egg dye solution with glow water.

Resources: If you don't want to blow your own egg or would like to try a larger eggshell, pre-blown shells are available from The Eggery Place. Alum is available at most grocery or drug stores but can also be purchased online from Talas. Powdered egg dye is available from Surma: The Ukranian Shop. Ready-made Crystal Egg Geode kits available from Professor Figgy's Fabulous Science Kits at professorfiggy.com.

Materials

  • Blown-out eggshell
  • Alum powder
  • White glue
  • Small paintbrush
  • Plastic or glass container
  • Egg dye
  • Hot water
  • Craft stick or spoon
  • Latex gloves
  • Drying rack or newspaper

Steps

  1. Step 1

    Start by blowing out a large white chicken egg and splitting it in half, lengthwise. The egg can be cracked by striking it against a surface or cut with a small pair of scissors. Make sure the inside of the eggshell is clean and dry.

  2. Step 2

    With a small paintbrush, apply white glue to the inside and cracked edges of each half of the eggshell and sprinkle with alum powder until completely coated. Set eggshell halves aside to dry overnight.

  3. Step 3

    The next day, prepare your growing solution in a glass or plastic container by using a craft stick or spoon to mix 2 cups of very hot water (almost boiling) with an entire packet of powdered egg dye. Be sure to wear latex gloves to protect your hands from the dye.Tip: Liquid food coloring can also be used to dye the geode -- 30 to 40 drops will adequately saturate the solution.

  4. Step 4

    Add 3/4 cup of alum powder to the hot dye bath and stir until completely dissolved. If there are remaining crystals in the bottom of the container, place the solution in the microwave for a few minutes to dissolve them. This will prevent alum from being drawn away from the geode.

  5. Step 5

    Once the alum is completely dissolved, let the solution cool slightly (for about 30 minutes) and then submerge one of the dried, alum-coated eggshells in the growing solution, allowing it to rest on the bottom of the container with the inside of the shell facing up.

  6. Step 6

    Set the container aside in a safe place overnight to allow the crystals to grow undisturbed. The longer the eggshell is in the solution, the larger the crystals in the geode will be. Twelve to 15 hours will usually result in a perfect geode.

  7. Step 7

    The next day, remove the geode from the growing solution very carefully (as wet crystals are quite fragile), being sure to wear latex gloves to prevent the dye from staining your hands. If you are not satisfied with the size of your geode crystals, return the geode to the growing solution and wait a day or two. As water evaporates from the solution, more alum will be deposited in your geode, increasing the size of the crystals.

  8. Step 8

    Place your geode on a drying rack or newspaper and allow to dry completely before handling.

  9. Step 9

    To grow a second geode in the other half of the eggshell, simply re-dissolve the crystals remaining at the bottom of the growing solution in the microwave and follow the instructions above starting at step 5.

Source
The Martha Stewart Show

Reviews (42)

  • AuntSun 3 Apr, 2014

    My nieces and I made these cool eggshell geodes. We let them sit in the colored alum solution for about 48 hours and they turned out gorgeous! Too bad it took so long to make them and then my cat sent them crashing to the floor within hours:(

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  • Nick C 30 Jul, 2013

    Make sure what you are getting is: Aluminum Potassium Sulfate (Forumula: AIK(SO4)2•12H2O)
    Example Link: http://www.sciencecompany.com/Aluminum-Potassium-Sulfate-500g-P16207.aspx

  • hotzeetotzee 20 Apr, 2013

    Can this process be done on Bisqueware ( unglazed pottery)?

  • hotzeetotzee 20 Apr, 2013

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  • ch_eled 4 Mar, 2013

    When I tried this with alum from the store, it worked beautifully. So...based on the instructions, I purchased 5 lb. of alum to do this with four classes of 4th grade science students. No crystals = many disappointed students. It would be really great...and would prevent some cash-strapped teachers and parents from wasting their $ ($30.00 in my case)...if the instructions stated that the alum must contain potassium. Most of us do not realize there are different forms of alum!

  • charlottew324 10 Feb, 2013

    Wonderful project-- my boys LOVED the crystal eggs!! I used the Granulated Alum made by Spice Trend ( green label). Each egg used about 4.5 of the small containers. I think next time I'll try ordering in bulk... We used food coloring and with 50 drops the eggs turned out great. Also, I added the hot water (microwaved to boiling) 1 cup at a time-- this was only because my measuring cup is small-- but it seemed to really dissolve all the alum very well. We also let them process for 22 hours.

  • Alexis S 6 Sep, 2012

    Hi! I was hoping to do this project with my friend's children the next time I'm babysitting, but he's highly allergic to eggs. Does this have to be done with real eggshells? Would a plastic one work? Or rocks?

  • craftyv 5 Jul, 2012

    Lovely stuff: Do they need a fixative to prevent deteriation (once completely dry of course)?? can't wait to try them.

  • Sharon Reynolds 5 Jul, 2012

    This does not work. I tried it following the instructions using alum purchased at a bulk food store. No crystals grew. Very dissappointed because I wanted to do this as a craft for children's church/VBS.

  • Ross Potts 6 Jun, 2012

    @lovelypancakes, you can use onion skin as a traditional dye. When you boil the papery skin, you make a lovely brown color for eggs, like a reverse scrimshaw!

    Also, go OLD, OLD school and use any number of flowers for different dyes.

  • kimlin 5 Jun, 2012

    I wonder if this could be done with rocks instead of eggs? I realize the rocks would look like inverted geodes because they would be convex, and the eggshells give the nice concave shape like a real geode split open. Since we're vegan, I wouldn't use real eggs. Thanks!

  • lovelypancakes 10 May, 2012

    in the other words, how can I find egg dye in Turkey? (:

  • lovelypancakes 10 May, 2012

    Is there any difference between food dye and egg dye? (: and how can I purchase egg dye?

  • lgomes 7 Dec, 2011

    If I wanted to do this with an ostrich egg, what would the ratio of water to alum be?

  • Frouski 24 Aug, 2011

    Hi Figgy01,
    Is it possible to use the same process on other surfaces such as glass, wood, metal etc. Also is there a way of stabilising the crystals. Was thinking of applying the process to jewellery pieces.

    Many thanks

  • figgy01 23 Aug, 2011

    Be sure that the alum you purchase (such as from the source, Talas, that I mention) contains Potassium (i.e. Potassium Aluminum Sulfate). Without it, the crystals will not grow. Some store-bought alums do not contain this and may also contain fillers that would hinder crystal growth.

  • jenobssuth 23 May, 2011

    So...sprinkle the alum powder onto the wet glue? How thick of a coating of glue to you paint? Also where in the grocery store or pharmacy do you find the powder? One last thing- so if I buy the alum anywhere but Talsa, use 1 3/4 cup? Thanks!

  • figgy01 3 May, 2011

    As far as the gold/bronze sheen on the purple eggs...that is an expression of certain metals that are in the dye that are released when it mixes with the alum. These were present even on the egg that I made for Martha. There is no way to prevent that from happening.

  • figgy01 3 May, 2011

    When I mentioned 1 and 3/4 cups of alum, that was a mistake on my part. I meant to say 3/4 of a cup. That is how much I use with the alum I get from Talas. However, with store-bought alum, you want to create a saturated solution. This may take more alum than the 3/4 of a cup mentioned. Just keep adding until no more will dissolve in the hot water.

  • TTwitchell 3 May, 2011

    I"m pretty sure when I watched the episode that Professor Figgy said to add 1-3/4 cups of alum power to the dye solution. Here it says to only add 3/4 cup so maybe that's what's causing the issues.

  • TeresaRenee 2 May, 2011

    Has anyone noticed the change in color of the egg/geo once it has dried?? Used the kit from Dr. Figgy and it worked great, beautiful purple color, but once it dried it now has a bronze/gold sheen to it. Any way to keep that from happening??

  • TheEggeryPlace 27 Apr, 2011

    The Eggery Place also has the dyes. So save on shipping and get them both. Look under Pysanky for the dyes on their website.

  • figgy01 21 Apr, 2011

    Cleaning the egg as much as possible is always a good idea. However, the alum, being a salt that is also used in pickling and preserving is very good at preventing anything from growing, especially mold.

  • kadi2 20 Apr, 2011

    egg

  • kadi2 20 Apr, 2011

    Keeping the membrene on the egg may cause the membrane to mold causing the cystrals to turn black.

  • kadi2 20 Apr, 2011

    The crystals will form if the membrane is left on., But it is possible that the membrane will mold in time turning the crystals black.

  • figgy01 18 Apr, 2011

    For those of you who had difficulty, where did you get your alum? It is important to make sure that it is Potassium Aluminum Sulfate. The source provided above (Talas) is where we get our Alum here at Martha - and it is very reliable and reasonably priced. Also, it is not necessary to remove the membrane from the egg. The glue and the alum will penetrate that and anchor to the eggshell just fine.

  • cindykik 18 Apr, 2011

    Kadi2 thanks for your comment. I did remove the membrane and follow the directions via this page vs. the tv show. I also tried again letting the solution cool much longer than 30 min thinking that would help but it didn't.

  • kadi2 18 Apr, 2011

    On the video you didn't address the cleaning of the egg or letting the solution cool for about 30 minutes before adding the egg.

    On the video you didn't adress the cleaning of the egg or letting the solution cool for about 30 minutes before adding the egg. People using only the video for instructions may be having problems. Also the membrane must removed.

  • maeleeal 17 Apr, 2011

    MINE DID NOT WORK EITHER.....SOOOOOO A WASTE OF TIME....AND A BIG DISAPPOINTMENT...

  • cindykik 17 Apr, 2011

    My eggs didn't work. I left them in the solution for over 15 hours and nothing happened. I'm very disappointed. Does anyone have any ideas?

  • Liudahl 16 Apr, 2011

    Found the dye at Surma: The Ukranian shop - order chemical analine dye, extremely intense shades.

  • Liudahl 15 Apr, 2011

    liudahl - what kind of dye do you use and where can I puchase it?

  • nikiley 14 Apr, 2011

    OMG! can you do this on other surfaces, like glass? And can you make it more permanent by putting some sort of protective finish on it?

  • MmePapillion 13 Apr, 2011

    The process of crystallization does not involve any chemical reactions.