Gray Concrete Slab is a slab-shaped variant of concrete, one of sixteen dyed colors that share the same crafting and behaviour rules. Gray Concrete Slab is a renewable resource and stacks up to 64.
Gray Concrete Slab is obtained either by crafting three blocks of concrete of the same color in a row, which yields six slabs, or by cutting a single block of that concrete in a stonecutter for two slabs per cut. Breaking it requires a pickaxe; without one, it drops nothing.
Placed like any other slab, Gray Concrete Slab can sit on the bottom or top half of a block space, and two matching slabs combine into a full double-slab block. It can be waterlogged. Gray Concrete Slab does not burn and will not ignite from nearby lava, and while the double form is not transparent, a single slab blocks light in Java Edition and diffuses sky light in Bedrock Edition.