This is a craft for older kids or adults to make but my kids loved playing with these. It was totally worth the work and honestly was not hard to make. You will need~
Clear glycerin soap
a long mold (we used a cup)
a non serrated knife
to make one crystal~
start by cutting up some soap and heat it in the microwave for 30 seconds. (add 15 till it is all fully melted) add food coloring and let cool. Once cool cut up into pieces, try to keep the pieces a good size and not small, but experiment with different cuts. Do this for each color you want to included in your crystal. I recommend only 3 max. Once you have all the colors place them in your mold in random order. Then heat up some more soap and pour it over the pieces till they are all covered. (don't color this soap or you will not see all the pieces) let it harden then using a knife go around the edges of the mold, ours came right out after this step. Again we used a cup that was rather slippery but maybe using cooking spray would help make them not stick? unsure
Once you have the soap out use the knife and square out the top and sizes as you wish and done!
We really liked playing with them in the sunlight and on our light table.
note~ once done the food coloring should not stain.