Stone Slab

Stone Slabs (also known as steps) are craftable blocks found very early in the game. They can be crafted using three cobblestone in a horizontal line. Stone Slab blocks were formerly called stair blocks until a proper stair block was added. Stone Slabs form a half block and can be walked up by the player without the need to jump.

Placing two Stone Slabs on top of one another will convert it into a full block and breaking it will only yield one stone slab instead of the two used to place it. These stone slabs affect lighting and liquids in the same manner full blocks do.

History
In Classic Survival Test, stone slabs could be obtained by mining a coal block because of the lack of inventory and crafting.

Trivia

 * Despite the fact that Sneaking gives a player an apparent height of 1.5 blocks, doing so does not allow the player to walk over a single stone slab with only a single empty block above it.
 * A player can not walk from a block of soul sand to a stone slab without jumping.
 * If you put two stone slabs next to each other in water, you can place a ladder on the stone slab (which is otherwise impossible). Additionally, the ladder is invisible.

Stufe