Quarterstaff as a magic staff

[Adjoint]

If a wizard has a quarterstaff for his bonded item, can he enchant it to make it into a magic staff? (not a magic weapon, a staff for casting spells)

Or the other way around: can a magic staff be used as a quarterstaff?

[Nixitur]

Adjoint wrote:

If a wizard has a quarterstaff for his bonded item, can he enchant it to make it into a magic staff? (not a magic weapon, a staff for casting spells)

Or the other way around: can a magic staff be used as a quarterstaff?

Technically speaking, staves are specific items, so you can't just turn anything into a staff. Many staves are mentioned to be made of something that would absolutely not work as a quarterstaff, like glass or whatever. Others are stated to work like another weapon, like a whip or a spade, so you obviously can't turn a quarterstaff into one of those.

There are, however, quite a few magic staves that are explicitly stated to work like quarterstaves. This isn't even close to all of them, just search for "quarterstaff" under Magic Items on AoN. I would say that you could absolutely turn your quarterstaff bonded item into such a staff.
I'm less sure if you could turn your quarterstaff into a magic staff that is not stated to work like a weapon nor made of something fragile. The rules state that "A typical staff also functions as a walking stick, quarterstaff, or cudgel", so as a GM, I would definitely allow you to turn a masterwork quarterstaff, even one that isn't magical, into a magic staff as long as it's reasonable from the description of the staff.

[GM Rednal]

I would also allow you to turn a Quarterstaff you were using into a magic staff, for basically the same reasoning as Nixitur. They are already described as acting like that, so why not allow it? Gotta have some kind of stick as the base anyway...

And this is especially true for the Staff Magus, who's a Quarterstaff/Magic Staff-using archetype.

[Big Blue 22]

Adjoint wrote:

If a wizard has a quarterstaff for his bonded item, can he enchant it to make it into a magic staff? (not a magic weapon, a staff for casting spells)

Or the other way around: can a magic staff be used as a quarterstaff?

Yes

Physical Description: A typical staff measures anywhere from 4 feet to 7 feet long and is 2 inches to 3 inches thick, weighing about 5 pounds. Most staves are wood, but an exotic few are bone, metal, or even glass. A staff often has a gem or some device at its tip or is shod in metal at one or both ends. Staves are often decorated with carvings or runes. A typical staff is like a walking stick, quarterstaff, or cudgel. It has AC 7, 10 hit points, hardness 5, and a break DC of 24. http://legacy.aonprd.com/coreRulebook/magicItems/staves.html