Dirt

Dirt is a block that was introduced very early in the game. It has 1 texture that is on all sides of the block. It is immensly abundant on natural maps, being the first few layers of blocks below grass and 3 - 4 layers above stone. When adjacent to a grass block and receiving sunlight, it can turn into grass itself.

Dirt blocks can be placed freely in Creative mode. In Survival, Indev, Infdev and Alpha, dirt can be mined easily. It is not strong against explosions, so obviously, it is not a good building material. Holes in large grassy fields often show past battles with Creepers, whether with the player or not. Dirt cannot be crafted into anything. However, using a Hoe it can be turned into farmland, if near water.