look at this! :O
Bake marbles at 325/350 for 20 minutes, then dump them in ice water. 
The inside cracks but the outside remains intact!
find out more here
(submit pictures if any of you do this!)

look at this! :O

Bake marbles at 325/350 for 20 minutes, then dump them in ice water.

The inside cracks but the outside remains intact!

find out more here

(submit pictures if any of you do this!)