A wizard's staff has got a gem on the end

[hcobb]

How do you treat a powerstone on a wizard's staff?

Is the stone itself a magic item for the rule of five?

[TippetsTX]

Just my own rule, but I don't allow multiple sources of mana to be combined into a single item or device. In fact, even touching two mana sources together can have undesirable consequences due the risk of something called the 'discordant resonance effect' (one of the unique aspects of how magic works in my campaign).

[Skarg]

Originally Posted by hcobb

How do you treat a powerstone on a wizard's staff?

Is the stone itself a magic item for the rule of five?

I treat it as one item for purposes of the Rule of Five, even if there are multiple powerstones embedded in one staff.

(But I also tend to use the rules from GURPS Magic where powerstones only recover ambient mana from the environment based on how close they are together, so if you have multiple powerstones embedded in one staff, they're going to split the mana available to recharge that way.)

[Helborn]

I have ruled that only the most powerful item works. Just like everything else. If you have multiple powerstones only the largest actually provides power or one of the largest ones if there several with same capacity. The others are just pretty things that can be sold for gold/silver.
However a manastaff with a powerstone provides ST from both.

And, yes, both count for the rule of five

Note that if it is not on the staff, then you can use one, switch it out for another one and use that one until empty