You can only cast this spell within a constructed room expansion of a structure you own, which cannot be the bonus expansion of the structure. Attempting to cast it elsewhere will cause the spell to fail, its spell slot expended.

The room expansion is removed, its room points refunded, and it no longer provides any benefit. After the spell is complete, this spell conjures a pile of gems or gold in the middle of the room equal to half its construction cost.

The room expansion vanishes, its benefits erased. In its stead, a glittering pile of gems or gold manifests, a tangible reward for reclaiming and repurposing the enchanted space.