Very Small Stone Tear  

 

Any experience mob. Most suggest green cons or barely light blue cons as most people believe it's basically the same amount of progression % per kill, despite the con. You also have to evolving enabled for the item on the evolution tab of the inventory window, and also have the item equipped. There is also a delay after equipping the item before kills evolve it to avoid people from evolving weapons by using a good one 90% of the fight then switching to the one needing evolution. Using a bandolier, even if not switching slots, still resets this for items in Primary, Secondary, or Ranged slots.

Avoid using clickies that need to be equipped in the evolving items slot as well when working on evolving it, to avoid resetting the delay.

Yther Ore.