Also known as: ソウルジェム, ジェム姦
A Gem birthed from a contract with Kyubey in Mahou Shoujo Madoka Magica. Proof that one is a Puella Magi; it is the source of the girls' magical power.
Not to be confused with the Soul Gem (Elder Scrolls)s from The Elder Scrolls, or one of the Infinity Gems.