Magma Block

A magma block is a light-emitting naturally-occurring block found in the Nether and the Overworld. It causes continuous damage while being stepped on, considered fire damage, except it does not light mobs on fire.

Breaking
Magma blocks can be mined using any pickaxe. If mined without a pickaxe, it drops nothing.

Natural generation
In the Overworld, magma blocks generate in aquifers. They also sometimes generate deep underground (level 15 and lower) in clusters of 1–8 blocks, and at the bottom of underground bodies of water.

Magma blocks also generate as a part of underwater ruins.

Magma blocks generate as part of ruined portals, as well as hoglin stable and treasure room bastion remnants.

Magma blocks also generate as part of delta in basalt deltas.

Blobs
Magma blocks can generate in the Nether in the form of blobs. Magma blocks attempt to generate four times per chunk in blobs of size 0–160, from altitudes Y=27 to Y=36 in all biomes. It can only replace netherrack.

Damage
Magma blocks damage most living entities standing on top of them, even if underwater, dealing of damage every tick, which can be reduced to once every half-second with damage immunity. Shulkers are among the mobs unharmed by magma blocks. Walking into the side of a magma block doesn't cause damage. Magma blocks do not destroy items. Damage from magma blocks does not reduce durability in netherite armor. Damage taken is considered fire damage and is reduced by armor, the Resistance effect, and Protection and Fire Protection enchantments. The player can avoid all damage by, being under the Fire Resistance effect, or by wearing Frost Walker boots.

Magma block damage does not set mobs or players on fire, and thus does not cook the animals that it kills.

Blocks that are the height of a trapdoor or lower (such as snow layers, carpet, repeaters or comparator) do not prevent a magma block from damaging mobs and players above it.

Magma blocks have a few specific death messages. If a player or named pet is killed simply from standing on the block, the death message displayed in chat is: "[player] discovered the floor was lava". If a player or named pet was attacked and knocked back to their death onto magma blocks, the message is: "[player] walked into danger zone due to [player/mob]".

Behavior
Magma blocks emit a light level of 3. They do not melt ice or snow.

Magma blocks emit smoke particles under rainfall, much like lava.

Making walls out of magma blocks prevents spiders (but not cave spiders) from climbing them.

Mobs avoid magma blocks that are in the way. Most mobs do not spawn on magma blocks (exceptions are magma cubes, zombified piglin, ghasts, and squid).

When a magma block's top is lit on fire, the fire burns indefinitely, similar to netherrack.

Bubble columns
When a water source is directly above a magma block, a whirlpool bubble column is created, going downward from the highest source block. Anything encountering the bubble column is pulled down, including items, boats, players, and mobs.

A player can restore breath underwater by entering a magma block's bubble column.

Note blocks
Magma blocks can be placed under note blocks to produce "bass drum" sounds.

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