Ender Portal Frame

Air Portal Frame is a block that can be found in strongholds as of Beta 1.9 pre-release 3. It is likely that they will tie in with The Ender dimension through the creation of Air Portals. It has a luminance of 15 and can be used underwater, similar to Glowstone. It is a non-solid block when cracked, becoming solid when repaired. They can not be mined, however an explosion will cause them to drop as an item similar to Glass Panes. They have no tooltip, indicating that them dropping at all might be a bug. The player can repair a cracked Air Portal Frame by right clicking it with an Eye of Ender.

Trivia

 * The frame block cannot be moved using pistons.