The next big trend in wedding cakes takes a cue from middle-school science class. Specifically, geodes. Geodes are volcanic creations that look just like normal rocks until they're split open to reveal a sparkling crystal interior.

Geode cakes use colorful sugar rocks to create intricate crystal formations, resulting in brilliant cracks that look carved right out of the frosting. These stunning creations are serious labors of love. It can take at least three days to grow the kinds of sugar crystals needed to decorate these cakes — and up to a week for larger rocks!

We’ve rounded up 10 of the best geode cakes on Instagram, and they’re all gorgeous works of art. Take a look and get ready to be inspired.