Floating Stones

Floating Stones level 1 (Blob of Water) can be acquired from Cloud Castles level 4 or higher, from leaving level 1 Snow Sculptures (Pile of Snow) to sit for a time, or from harvesting Floating Stones level 4 or higher.

Floating Stones can be harvested for Sinkholes, starting at level 5.

Object information
There are currently 12 different levels of Floating Stones, with level 12 being a Wonder.