Cobblestone

Cobblestone is a Block, obtained from mining Stone, Cobblestone, or from Cobblestone Minions.

Obtaining
Cobblestone can be obtained from mining Stone, It can also be gathered from cobblestone generators and Cobblestone Minions on your Private Island found in the Private Island (and 8 can be found in the starter chest), Coal Mine, Gold Mine, Deep Caverns, Dwarven Mines and Crystal Hollows. Mining Stone or Cobblestone grants  XP.

Collection
Collecting cobblestones increases the player's cobblestone collection, which grants useful items and perks upon collecting certain amounts of cobblestones.

Usage
Cobblestone can either be smelted in a furnace to make normal stone, mined with Pickaxes / Drills enchanted with to obtain  it also counts for progression towards the rock pet