Trap the soul

Trap the soul is a sorcerer and wizard spell that allows the caster to trap the life force and material body (if any) of a creature inside a gem. The creature can only be released if the gem is broken. The caster can complete the spell normally, or by creating a trigger object. If a trigger object is used, the creature becomes trapped in the gem as soon as it touches the object. The more powerful the creature being trapped, the more valuable the gem must be. If the gem is not of a high enough value compared with the power of the creature, the gem will shatter instead of functioning properly.

Realmslore
Some of the inhabitants of Esh Alakar in Maztica are trapped in gems beneath the ruins of the site, after falling victim to this spell.