Basalt

Basalt is a block found in the basalt deltas in the Nether along with soul sand valleys and bastion remnants.

Basalt drops as an item if mined by any pickaxe. If mined by any other tool, it drops nothing.

Basalt generates naturally as basalt pillars, which are found in the soul sand valley biome. They also generate in the basalt deltas biome as regular terrain and as part of basalt columns. In Java Edition, they also generate in blobs, which attempt to replace netherrack 75 times per chunk in blobs of radius 3–7 from levels 0 to 127 in basalt deltas biomes.