Eternal Ice unlocks at level 31.
There are several ways to acquire it:
- Produce at the Ice Factory
- Get it from the Ice Hoof
- Buy a pack of it from the store
- Get it from chests
- Get it from the Wishing Tree
- Get it from the Spirit Wheel after building the Ice Factory on the Marble Fjord
- You can also collect it from your neighbors or get it as a gift.