It's almost too simple. It's almost laughable. But as a Mom of three kids who did this craft with her children twice when they were younger I am telling you... they loved this craft. I loved it because it was as simple as going out to the backyard landscaping and grabbing a few rocks and then finding the pencil box of discarded crayons. Add a piece of foil and you've got a craft ready to go!
Find rocks that are semi-smooth for even coverage. Using bright crayons, color as much of the rock as you can using patterns, swirls, solids... whatever your little helpers can come up with.