Slab

Slabs are half-blocks.

Obtaining
Stone-type slabs require a pickaxe to mine. Wooden slabs can be mined with anything, but an axe is quickest.

Natural generation
Stone slabs can be found naturally in villages lining the roof of blacksmith shops and inside some of the buildings where they form counters. They are also found in strongholds where they are used in some of the stairs, ledges and torch pillars. Sandstone slabs can be found naturally in desert villages, desert wells, and desert temples.

Crafting
Wooden slabs must be crafted entirely from one type of wood, but by the same token, they keep the type and color of the wood used, thus "Birch Wood Slabs" and so forth.

Behavior


Slabs are treated as a whole block by other blocks and liquids. Two slabs of the same type can be placed one on top of one another to make a full-size block, but different slab types cannot be mixed in this way.

Redstone can be connected to the wire on the side of the slabs. Redstone placed on top of an upside-down slab can receive signals from an adjacent block of redstone one block lower but cannot transmit signals to it. This is why "ladders" made from upside-down slabs, as pictured to the right, can transmit redstone signals up, but not down.

Mobs can spawn on top of upside down slabs and on double slabs.

Due to the way blast rays propagate from an explosion, bottom-half slabs provide extremely effective absorption to explosions directly on top of them.

Despite how sneaking lowers the player's eye level half a block, doing so does not allow the player to walk over a single slab with one block of air above it because of the player's true height. A player cannot walk from a block of soul sand to a slab without jumping.

Data values
The slab blocks use IDs and data values to differentiate between types. They also have block states which will replace data values in the future.

Double stone slabs

 * Block 43


 * Block 181

The Full Stone, Sandstone, Quartz and Red Sandstone Slabs have a top texture on all sides.

Stone slabs

 * Block 44


 * Block 182

Double wooden slabs

 * Block 125

Wooden slabs

 * Block 126

History
{{History||1.3.1|snap=12w17a|{{BlockSprite|wooden-slab}} {{BlockSprite|birch-wood-slab}} {{BlockSprite|spruce-wood-slab}} {{BlockSprite|jungle-wood-slab}} New slabs were added for the four different types of wood planks, replacing the old wooden oak/"stone" slab. These new slabs were vulnerable to fire, and could be collected faster with an axe than with a pickaxe. Wooden slabs already crafted or placed in the world remain the old 'stone' type. {{History|||snap=12w25a|Redstone (including repeaters, torches, levers, and pressure plates) and rails can now be placed on slabs and stairs positioned upside down.}} {{History|||snap=12w26a|Mobs can now spawn on upside down slabs.}} {{History||1.4.2|snap=12w39a|Slabs interact properly with lighting now; when slabs are placed upside down, they now accept light from light sources themselves, and no longer block light to surrounding blocks; they no longer cast the shadow of a full-sized block. |Smooth lighting on slabs is slightly bugged.}} {{History||November 28, 2012|link={{tweet|Jeb_|273775616162164736}}|Jeb tweeted a picture of himself crafting nether brick slabs.}} {{History||1.4.6|snap=12w49a|{{BlockSprite|nether-brick-slab}} Added nether brick slabs, which causes the smooth stone full half-slab to change its damage value to 43:7}} {{History||1.5|snap=13w02a|{{BlockSprite|quartz-slab}} Added quartz slabs. The formerly unused slab type, known as the smooth stone full half-slab (see gallery), was removed from the game. Its data values were replaced with the nether quartz slab.}} {{History||January 22, 2013|link={{reddit|1722hf/the_smooth_full_halfslab_will_become_438}}|Jeb states that the smooth stone full half-slab will be re-implemented with a value of 43:8. The smooth sandstone slab will also be implemented, with a value of 43:9. He also stated that they may be obtained legitimately later. }} {{History||1.5|snap=13w04a|{{BlockSprite|sandstone-top}} The smooth stone full half-slab is re-implemented with a value of 43:8. The smooth sandstone full half-slab is also added, with a value of 43:9.}} {{History||1.7.2|snap=1.7-pre|{{BlockSprite|acacia-wood-slab}} {{BlockSprite|dark-oak-wood-slab}} Added acacia and dark oak slabs.}} {{History||1.8|snap=14w02a|Stone brick slabs can now be used to craft chiseled stone bricks. {{History|||snap=14w25a|Double Stone slabs and Double Wooden slabs can no longer be obtained as an item.}} {{History|||snap=14w32a|{{BlockSprite|red-sandstone-slab}} {{BlockSprite|red-sandstone-top}} Added red sandstone slabs, including full slabs.}} {{History|||snap=14w33a|Stone slabs can no longer be crafted using granite, diorite, andesite, or their polished counterparts.}} {{History|pocketa}} {{History||0.1.0|{{BlockSprite|stone-slab}} Added stone slabs.}} {{History||0.3.0|{{BlockSprite|wooden-slab}} {{BlockSprite|brick-slab}} {{BlockSprite|cobblestone-slab}} Added wood (original oak), brick and cobblestone slabs.}} {{History||0.6.0|{{BlockSprite|sandstone-slab}} {{BlockSprite|stone-brick-slab}} Added sandstone and stone brick slabs. {{History||0.7.3|Wooden slabs crafted during and after this update are now flammable. Existing wooden slabs (which have stone properties) are now tagged "Fake Wood Slab" and drop real wooden slabs.}} {{History||0.8.0|snap=build 2|{{BlockSprite|birch-wood-slab}} {{BlockSprite|spruce-wood-slab}} {{BlockSprite|jungle-wood-slab}} Added birch, spruce and jungle wood slabs.}} {{History||0.9.0|snap=build 1|{{BlockSprite|acacia-wood-slab}} {{BlockSprite|dark-oak-wood-slab}} Added acacia and dark oak wood slabs. {{History|console}} {{History||TU1|{{BlockSprite|stone-slab}} {{BlockSprite|wooden-slab}} {{BlockSprite|sandstone-slab}} {{BlockSprite|cobblestone-slab}} Added stone, wood (original oak), sandstone and cobblestone slabs.}} {{History||TU5|{{BlockSprite|stone-brick-slab}} {{BlockSprite|brick-slab}} Added stone brick and brick slabs.}} {{History||TU9|{{BlockSprite|birch-wood-slab}} {{BlockSprite|spruce-wood-slab}} {{BlockSprite|nether-brick-slab}} Added birch wood, spruce wood and nether brick slabs. {{History||TU12|{{BlockSprite|jungle-wood-slab}} Added jungle wood slabs. {{History||TU14|{{BlockSprite|quartz-slab}} Added quartz slabs. {{History|pi}} {{History||0.1.1|{{BlockSprite|stone-slab}} {{BlockSprite|wooden-slab}} {{BlockSprite|brick-slab}} {{BlockSprite|cobblestone-slab}} Added stone, wood (original oak), brick and cobblestone slabs.}} {{History|foot}}
 * Stone slabs could be crafted using granite, diorite, andesite, or their polished counterparts.}}
 * Slabs can be placed on the top half of blocks.
 * The recipes for crafting slabs gives 6 slabs instead of 3 slabs.}}
 * Sandstone slabs now spawn naturally in villages.
 * Slabs now have the correct name.}}
 * Wooden slabs crafted during and after this update are now flammable. Existing slabs (which have stone properties) are not stackable with the new slabs.}}
 * Slabs can be placed upside down. Items can be placed directly on upside down slabs.}}
 * Changed placement of half blocks & other blocks on half blocks.
 * Changed placement of upside down slabs.}}

Dirt slab


Before stone slabs were added to 0.26, Notch ran a test of dirt slabs. They were never added to the actual game and were only mentioned once. They replaced all dirt blocks and did not grow grass on top.

Trivia



 * Slabs let a small amount of light pass through their edges. This light is only visible with Smooth Lighting is turned on, and does not affect mob spawning or other light-dependent processes.
 * The exception of this is that any light directed through a slab does not affect any block's light values north of the source.
 * Mobs see a slab as a full block. Therefore, by placing an upside down slab above a slab with a block in between, there will be sufficient space for the player to walk through. Mobs, however, will see one block of space in between and won't get through. This does not apply to baby zombies and spiders, because they are only one block tall, and to slimes, as they will hop towards the player even if there is something obstructing the way.
 * You can sneak walk off slabs at ground level.
 * Minecarts on powered rails will not be repelled from a slab. They will, however, be repelled by a slab with a minecart on top.
 * If you set a slab on the top half side of any block under water, it will displace as much of it as a whole block. Not only can you grab a quick breath of air, but you can see as clear through the water as looking over the land above the surface than in it itself.
 * When an upside down slab is pushed from the bottom by a piston (or regular slab pushed from the top), it is pushed without having contact from the piston. The same idea can also be made when pulled by a sticky piston.