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|First Appearance||Survival Test 0.26-|
|Type of Block||Solid|
|Data Values||Hex: 31 Dec: 49|
Obsidian is also the only material that can make a portal to The Nether , as of the October 31st Halloween Update. To make a portal, a frame made of Obsidian must be erected, standing 4 blocks long and 5 blocks high up including the frame to a square 23 by 23 high as of release 1.7, and the remaining space should be left open. The corner blocks need not be included in the rectangle. Then, the bottom Obsidian blocks should be lit on fire with a Fire Charge or Flint and Steel , though Lava will not work. After this is done, the portal opens, granting access to The Nether. Obsidian is also resistant to explosions, with the exception of the Wither 's skeleton skull attack. Because of this fact, many players have constructed execution-by- TNT rooms out of Obsidian.
In addition to the TNT execution rooms, multiplayer servers find Obsidian to be the best defensive structure, as it is nearly impossible to destroy. Making a wall around a city in Obsidian may take a long time, but is well worth the defense when defending from an attack, especially since it renders TNT useless.