Minecraft wiki entry for Things_not_to_do, associated text: The player should avoid building with dirt, sand, snow, and netherrack, because they are weak materials with a low blast resistance, unless it's a temporarily structure or as a temporary base (creepers cannot blow if there is a one block wall between the player and the creeper). They are easily destroyed by creepers or TNT. Instead, the player should use cobblestone, which is a cheap, abundant, and tough alternative. Later on in the game, the player may want to make their main base out of more varied blocks.