Cobbled Deepslate block in Minecraft

What it does

The game treats it as a stone crafting material, so it can replace cobblestone in stone tools, in the Furnace and in the Brewing Stand. You will collect plenty of it while looking for diamonds, so there is no need to carry cobblestone down.

It is harder than cobblestone and takes noticeably longer to mine, but it resists explosions just as well. That hardness is why tunnels through the deepslate layer go slower.

As a building block it opens a whole palette: slabs, stairs and walls, then Polished Deepslate, deepslate bricks, tiles and chiseled deepslate, all of which can be cut on a Stonecutter. Smelting it gives a deepslate block back.