End Portal Frame

End Portal is a block that can be found in Strongholds. It resembles an End Stone with a decorative bluish-green top, with sides decorated in hollow rounded rectangles with the same color as the top. They are found in a 12 block ring shape within a room over a pool of lava and a staircase containing a Silverfish spawner.

An interesting quirk of the end portal frame (and the monster spawner) is that they are transparent in their rendering only - unlike all other transparent blocks, they can have torches and redstone placed on them, conduct a redstone current, will suffocate mobs, and more.

Uses
Some of the blocks have an Eye of Ender inserted into it. Using other Eyes of Ender on the rest of the blocks inserts them to the top of the blocks. Once an Eye of Ender has been inserted in all 12 Frame blocks, then the Ender Portal will activate and the player can pass through to access The End. Additionally, like Bedrock, the frame blocks are only destructible in Creative Mode.

Since snapshot 13w18, End Portal blocks will output a redstone comparator signal when an eye is present, making

Trivia

 * Like Bedrock, End Portal Frames are indestructible without the use of Creative mode or mods. When broken in such a way while activated, the portal itself will not be deactivated, unlike Nether Portals. This is probably due to End Portals not being meant to be destroyed, while Nether Portals can be destroyed, as they are made of Obsidian.
 * When broken, these blocks make the same breaking noise as glass blocks.
 * While not readily apparent from a visual appearance of the End Portal Frame, there is a "front face" to the block which must face inward as it is being placed on a map in order for the End Portal to be created when the Eye of Ender is placed in the frame. While End Portal Frames can be placed in random directions and the portal will activate, the final block must be "facing" inward if it is the final Eye of Ender to be placed into the frame.
 * Because there are only three Strongholds in every world, there are only 36 of these blocks in each map. (12 in Xbox 360 Edition)

Endportal (Block) Cadre de portail de l'air End Portaal Frame Rama portalu Kresu 末地传送门框架