I've made dozens of crackle marble necklaces for gifts. So easy and cheap! Well, not that I'm cheap but you can do a lot with them. Hang from a branch tree on ribbons or silver chains for a necklace tree that visitors can select one as a little gift. They might even find their birthstone. I use the bags of marbles in mixed colors. Pour the marbles in a very hot skillet being sure to keep the skillet moving as you swirl the marbles around gently until they are very hot. Pour the hot marbles into a ice water bath. They will crackle. I glued the bells on the one shown for a necklace.
I'm now enjoying coffee and my favorite creamer as I decorate the house = LOVE!