ダークジュエル
When [[Hoshina Utau]] character transforms with [[Hinamori Amu]]'s [[guardian chara]] [[Dia (shugo chara!)|]], she turns into Dark Jewel. Similarly to Dia, she has a [[diamond (shape)|]] motif.

However, because Utau is not Dia's owner, the transformation drains a lot of her energy and does not last long.
dark jewel