The Floating Islands are spawned randomly upon world creation. They are located hgih up in the sky, but can sometimes be seen from the surface or when jumping. A Floating Island will usually have gold and other ores inside of it, and a building on the surface which is sometimes made of Gold Bricks. The building will also contain a Chest which will contain a rare item and various other items. Harpies will also attack the player while on the Floating Island, so it is advised to stay inside the building or under the surface.
 How to Find Them
The Floating Islands are considered hard to find by many players, but they can be very easy to find if you know how and where to look. The easiest way to find a floating island is to start a new world and walk left or right until you find a deposit of clay on the surface. Once you find the clay, there should be a Floating Island directly above you. Another way to find it is to build a long bridge across the sky. This way usually requires more time and effort, especially when playing on a large world.