Grass is a Vanilla Minecraft block which covers a large portion of the surface of a randomly generated world. When broken, it drops a Dirt block. It mainly covers the floor of biomes such as Forest, Plains, Swampland, Jungle, Taiga (under the snow), and Extreme Hills.
It takes 0.75 seconds to break Grass by hand, 0.4 seconds with a Wooden Shovel, 0.2 seconds with a Stone Shovel, 0.15 seconds with an Iron shovel, and 0.1 seconds for both a Gold Shovel and Diamond Shovel. To obtain a Grass Block without it dropping as dirt, you will need a Shovel/Pickaxe with the Silk Touch enchantment. However, 2 UU-Matter can create 16 Grass Blocks. You can also use a Alchemical Tome in a Transmutation Tablet or from a Scrap Box to obtain it.