This is what I did with my empty egg shells:
feedback here...I love crystals and especially geodes, so how could I pass up the chance to turn some empty egg shells (thus the tutorial on how to create crystal filled geodes). I saw it here at http://www.marthastewart.com/343344/crystal-egg-geodes. 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 (http://www.alisonspantry.com/ ) 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.
1 empty (blown) egg shell
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)
feedback here...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.
feedback here...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.
feedback here...Put 1 cup water in the bowl. This water needs to be hot. Room temperature water can only hold so much dissolved medium (by medium I mean things like, alum, sugar, salt, Epsom salts, etc.). At this point it is called “saturated”. As you heat the water, it is better able to absorb more medium, so you keep adding heat to the water and you keep stirring in more medium until it just can’t hold any more, then the solutions is called “super saturated”. A super saturated alum solution is what we are after. So I heated the water for 1 minute in the microwave.
feedback here...I then slowly added 6 tablespoons of alum, stirring as I went, (it bubbled a little at first) the goal being to dissolve all the alum; this means no crystals in the bottom of the bowl. I learned that 6 heaping Tbs. was too much and 6 level Tbs. was too little, so do something in between.
feedback here...put the solution in the microwave for 30 more seconds and stir again. That should do the trick. Let the solutions sit at least 15 minutes but no more than 30 minutes. You need your solution to be cool enough to handle, yet if you wait too long your crystals will start falling out of the solution into the bottom of the bowl and not into your egg shells.
feedback here...Pour half of your solution over each egg half (again it fuzzed a little, I think it was reaction between the calcium carbonate in the shell and the alum, please don't make me balance an equation to figure this out),and set aside for 15 + hours. Alum is great for this project because it is nontoxic, and it makes great crystals in very little time (compared to a week or more for salt or sugar crystals).
feedback here...One thing I noticed was that the dye was mainly absorbed by the egg shell, not by the crystals. Yet the crystals are transparent enough that they reflect the color. Soooooo Cool! Now to get some more Alum and this time use neon dyes! I love it and I hope you ENJOY!