Stockdale said:
I'm gonna chime in with Darthkilmor. I recall reading somewhere (3.0 DMG ?) that it was two or three stones. I further recall (and I might be wrong) that they did take up the head slot for magic items.
Nope to both.
First of all, there isn't technically a "head" slot. There's a "headband, hat, helmet, or phylactery on the head" slot, and a "eye lenses or goggles on or over the eyes" slot. Since ioun stones clearly aren't any of these (and the DMG gets specific on names of things, so it's clear which slot they go into), they don't take up a slot on the body. Items whose names don't explicitly describe the slot they occupy almost always list the slot in the description of the item. No such information exists in the DMG or SRD description of ioun stones.
Similarly, if there were a limit on how many a character could "wear" at once, again, it'd be in the description, and again, there's no such information in the description.
Additional indirect evidence that they don't take up a slot: the ioun stones that grant a +2 enhancement bonus to an ability score cost 8,000gp, twice as much as items like Gloves of Dexerity +2 or Gauntlets of Ogre Power +2, which do
exactly the same thing. Further, in the section of the DMG about creating magic items, it says that a magic item that doesn't take up a slot on the body costs 2x the standard costs, and it even lists ioun stones as an example!
