Its best modifier is Godly or Demonic. Both modifiers increase the average damage output by the same amount. Mechanical tools can only have universal prefixes, because they can't have their speed modified.
This tool functions much like drills or chainsaws, in that it mines via a "machine" with constant directed contact, rather than being swung repeatedly at targets. While there are several drills and chainsaws fulfilling pickaxe and axe duties via a machine method, the Chlorophyte Jackhammer is the only such tool fulfilling hammer duty.