Question regarding stat increases from seperate items

[Amune Eversong]

Would a Scarlet and blue (+2 INT), and a Headband of Vast Intellect's bonus stack? Thanks for your help!

[Oladon]

You mean a scarlet and blue sphere (ioun stone), not a "scarlet and blue".

No, they don't stack, as the bonuses provided by both are enhancement bonuses.

[GermanyDM]

I agree with Oladon; these two items don't stack.
It appears that there are some ioun stones in Pathfinder accessories with stacking enhancement bonuses (up to a limit), but their descriptions clearly indicate this. And the scarlet and blue ioun stone isn't one of them.

[Amune Eversong]

All right, thank you both very much for your help. And yeah I did mean the sphere.

[Horselord]

What if multiple +2 Int Ioun stones are worn? The bonuses don't stack but is it a cheap, effective way to max out a lot of skills?

[Jeraa]

Horselord wrote:

What if multiple +2 Int Ioun stones are worn? The bonuses don't stack but is it a cheap, effective way to max out a lot of skills?

It shouldn't be. The bonus skills you get from a Intelligence boosting item represent stuff you now know from your increases Intelligence. If the intelligence boosts are stacking, then you aren't getting any smarter, and you shouldn't gain the additional skills.