From the blog "Sandbox Update Notes"

+ Added small and large rocks which generate across the surface (will be covered in snow or moss at times depending on biome) + Added Snowball (dropped when breaking snow, and can be obtained by shoveling snowy rocks) + Added Sandstone item + Added small bushes which generate on grassy surfaces (can also have snow overlay), dropping wood when broken + Added Char biome (name subject to change), a volcanic biome + Added Ash tile + Added Copper Tools (Axe, Hammer, Hoe, Pickaxe, Shovel S