Wondrous item, rare
If the stone is touching the ground, you can use an action to speak its command word and summon an earth elemental, as if you had cast the conjure elemental spell. The stone can't be used this way again until the next dawn. The stone weighs 5 pounds.
Stone of Controlling Earth Elementals is a rare wondrous items. It needs no attunement, so it's an easy pickup for any character. Drop it into a hoard or a shop that matches its rarity to keep your treasure feeling earned.
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370+ magic items as illustrated, printable cards, so you can hand Stone of Controlling Earth Elementals to a player as a prop instead of a line on a loot list.
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