It is darker than normal dirt and has a reddish brown hue. It spawns in patches in Mordor, its sub-biomes and biome variants. It composes the roads in Mordor along with gravel. Mordor dirt is the primary block in the terrain of the Eastern Desolation.
Mordor dirt can be used as a building material, similar to regular dirt, although it doesn't make for particularly pretty-looking bases. It's also very easy to mine through, even with your hands, and a shovel or bomb can make short work of a large quantity of Mordor dirt. A good use for Mordor dirt is making paths between your different bases. It can not be hoed to grow food.