# Ioun Stone of Mastery > [!info] Item Details > | | | > |---|---| > | **Category** | Wondrous Items | > | **Rarity** | Legendary | > | **Attunement** | Yes | > | **Source** | DMG p.176 | --- ## Description When you use an action to toss this stone into the air, it orbits your head at a distance of 1d3 feet and confers a benefit. Another creature must use an action to grasp or net the stone to take it, either by making a successful attack roll against AC 24 or a successful DC 24 Dexterity (Acrobatics) check. You can use an action to seize and stow the stone, ending its effect. **Appearance:** pale green prism. Your proficiency bonus increases by 1 while this stone orbits your head. --- ## Properties - **+1 to proficiency bonus** while orbiting. - Requires attunement.