Nether Reactor

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Nether Reactor
Nether Reactor.png
Consists of
First appearance

Pocket Edition Alpha 0.5.0

The Nether Reactor is a player-built structure which, when activated, spawns large quantities of normally rare or unobtainable items.

Creation[edit | edit source]

The reactor is constructed by placing gold blocks, cobblestone, and a nether reactor core in the 3x3x3 arrangement shown below. Air blocks are required on the middle and top layers. If the structure is incorrect, attempting to activate the reactor will result in the client message "Not the correct pattern!".

Top layer.

Middle layer

Bottom layer

Behavior[edit | edit source]

The 'Nether Spire'

Tapping the core will activate the reactor, sending the client message "Active!". Immediately after activation, a massive 35×17×17 structure of netherrack with multiple rooms, unofficially referred to as a "Nether Spire",[1] is spawned around the reactor. The bottom room, which contains the reactor, replaces all blocks other than those of the reactor with air, while blocks in the upper levels remain intact.

Items will begin spawning randomly in the reactor room. These can be glowstone dust, nether quartz, cacti, sugar canes, both types of mushrooms, pumpkin seeds, and melon seeds. Zombie pigmen are also able to spawn. It is advisable to empty out one's inventory beforehand so that no items are missed, other than any weapons used to fight the zombie pigmen (unless playing in peaceful difficulty). During this stage, the blocks that make up the reactor will turn into glowing obsidian, and the core will adopt a red texture representative of being active. If the player mines the active core, all aspects of the reaction will freeze.

After 45 seconds the reactor cycle will end, causing the spire to 'blow up', leaving holes in its walls. At this point, the time is set to night. The reactor is replaced with a 3×3×3 box of obsidian containing the core, which now has a smooth, blackened texture representative of being 'burnt out'. If the player builds a new reactor around the burnt out core, the spire will generate, but no other behaviors associated with the reactor will occur. Because of this, netherrack is renewable.

The reactor cannot be activated in Creative mode.[1]

Conditions[edit | edit source]

  • All players must be within the spire's area
  • The reactor must be built at least 32 blocks below cloud level, or 4 blocks above the void
  • The player must be standing level with the reactor

Glowing Obsidian[edit | edit source]

Glowing Obsidian
Glowing Obsidian.png


Solid Block,Technical






Yes, 12

Blast resistance



A diamond pickaxe or better is required to mine this block


Pocket Edition



Data value

dec: 246 hex: F6 bin: 11110110

Glowing obsidian is a block which only generates when the Nether reactor is activated. Upon activation, the blocks that make up the reactor turn into glowing obsidian.

Properties[edit | edit source]

As the name suggests, glowing obsidian is a solid block that gives off light similar to glowstone, but slightly dimmer. It does indeed glow, but its physical properties are closer to obsidian. It takes the same amount of time to mine as obsidian. Instead of dropping itself, it drops a normal obsidian block. The block will emit red smoke particles within close proximity to it so long as it exists, similar to the particles redstone creates when activated. Although in the Nether reactor the block seems to spawn items around it, it is not the block itself that acts like this, nor will it spawn items if placed normally. The block turns into obsidian after a short amount of time. Otherwise it is simply an aesthetic block, as it has the same blast resistance as normal obsidian.

History[edit | edit source]

Pocket Edition Alpha
September 5, 2012 A image of the Nether reactor is tweeted by Johan Bernhardsson. At that time, it used iron blocks rather than cobblestone to activate.
0.5.0 Added the nether reactor. Spire is made of obsidian.
0.6.0 The spire is now composed of netherrack.
0.8.0 Now spawns pumpkin seeds.
0.11.0 build 1 Can no longer be activated at bedrock level.
The day/night cycle now continues upon mining the active core.
Upcoming Pocket Edition
0.12.1 build 1 The Nether reactor is made obsolete by the addition of the Nether. While the Nether reactor blocks still exist they serve no purpose.

Issues[edit | edit source]

Issues relating to "Nether Reactor" or "Reactor" are maintained on the issue tracker. Report issues there.

Trivia[edit | edit source]

  • The spire is composed of over 25 stacks worth of netherrack.
  • Excluding the core, any part of the reactor can be mined after activation and it will still function. This way, the player can recycle the expensive gold blocks. If they're fast enough, they'll have time to mine all four gold blocks before they turn to glowing obsidian.
  • Because the spire cannot replace blocks past the world border, when the reactor is activated near the edge of old worlds the player will be able to see the time set to night.
  • If the nether reactor core is mined out while the nether reactor is active, the glowing obsidian will not turn into obsidian after the reactor deactivates. This also causes the reactor to stop spawning items and zombie pigmen.

Gallery[edit | edit source]

References[edit | edit source]

  1. a b