Wondrous Item, Rare (Requires Attunement)
Roughly marble sized, Ioun Stones are named after Ioun, a god of knowledge and prophecy revered on some worlds. Many types of Ioun Stones exist, each type a distinct combination of shape and color.
When you take a Magic action to toss an Ioun Stone into the air, the stone orbits your head at a distance of 1d3 feet, conferring its benefit to you while doing so. You can have up to three Ioun Stones orbiting your head at the same time.
Each Ioun Stone orbiting your head is considered to be an object you are wearing. The orbiting stone avoids contact with other creatures and objects, adjusting its orbit to avoid collisions and thwarting all attempts by other creatures to attack or snatch it.
As a Utilize action, you can seize and stow any number of Ioun Stones orbiting your head. If your Attunement to an Ioun Stone ends while it’s orbiting your head, the stone falls as though you had dropped it.
The type of stone determines its rarity and effects.
Reserve. This vibrant purple prism stores spells cast into it, holding them until you use them. The stone can store up to 4 levels of spells at a time. When found, it contains 1d4 levels of stored spells chosen by the DM.
Any creature can cast a spell of level 1 through 4 into the stone by touching it as the spell is cast. The spell has no effect, other than to be stored in the stone. If the stone can’t hold the spell, the spell is expended without effect. The level of the slot used to cast the spell determines how much space it uses.
While this stone orbits your head, you can cast any spell stored in it. The spell uses the slot level, spell save DC, spell attack bonus, and spellcasting ability of the original caster but is otherwise treated as if you cast the spell. The spell cast from the stone is no longer stored in it, freeing up space.