Dirt

Dirt is a block that was introduced very early in the game. It has an identical texture located on all sides of the block. It is immensely abundant on normally generated 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, there is a change that it can turn into Grass block itself.

Dirt blocks can be placed freely in Creative mode. In Survival, Indev, Infdev and Alpha, dirt can be mined easily. However, it does not have a strong resistance against explosions, so it is not a recommended building material. Holes or indents in large grassy fields may show past battles with Creepers or intances of random mining by players. Dirt cannot be crafted into anything, but may be transformed into fertile farmland by using a Hoe.

Trivia

 * Dirt is the second most common resource, next to Stone.