As written, the required components for scrying are pretty confusing; read literally as-is, an arcane caster requires both a pool of water and a fancy mirror, whereas a divine caster requires a divine focus and a fancy mirror.
However, that almost certainly wasn't the intent; it looks like the description for Scrying suffered a little in the copying from 3.5e to Pathfinder. The original 3.5e version is much more specific about the requirements the spell has:
Components: V, S, M/DF, F
Arcane Material Component
The eye of a hawk, an eagle, or a roc, plus nitric acid, copper, and zinc.
Wizard, Sorcerer, or Bard Focus
A mirror of finely wrought and highly polished silver costing not less than 1,000 gp. The mirror must be at least 2 feet by 4 feet.
A holy water font costing not less than 100 gp.
A natural pool of water.
This list is notably absent from the Pathfinder version, which is in keeping with Pathfinder's general trend of trying to simplify spell component requirements, though it seems that the intention was to retain a difference between the arcane and divine versions of the spell. It doesn't help that the 3.5 version of the spell was pretty unusual to begin with, as it specifies a unique divine focus (whereas the general rules for components say a divine focus is always an appropriate holy symbol or similar faith-related item), and thereby muddies the waters somewhat as to the definitions of things.
In my game, I would just refer to the components specified by the 3.5e version of the spell to make sense of Scrying. The arcane material component will almost never be important because of the ubiquitous spell component pouch anyway, so all you really need to worry about is the different focus that each version of the spell requires.
Alternatively, as HeyICanChan suggests, you could houserule the component description to read:
Components: V, S, F (a silver mirror worth 1,000 gp)/DF
And then note in the text of the spell that a divine caster needs a pool of water in which to scry, as well as their normal divine focus; it's possible that this is closest to what was intended for Pathfinder's simplified version of the requirements.