Shovels or Spades are the fastest item to use to dig Dirt, Grass Blocks, Sand, Gravel, and Snow. Since Update 0.9.0, there is a glitch where occasionally, a stone shovel will have the digging speed of a diamond shovel.
Shovels can be crafted with Wooden Planks, Cobblestone, Iron Ingot, Gold Ingots, and Diamonds. You also need 2 Sticks to craft a shovel. Shovels are the only tool that can shovel snow and to get a Snowball. If you dig it with a hand, or anything else besides a shovel, you will get nothing. One of the easiest ones to use is the stone shovel.