Opal

The Opal (オパール, Opāru) is an item in the first Suikoden. The Opal is a quest item needed to recruit Esmeralda in Antei.

Information
The Opal is a very valuable and rare jewel, held by the Nightmare creature dwelling in Soniere Prison. Its beautiful lustre captivates the attention of women the world over, making it highly prized.

When the aristocratic Esmeralda was first approached by the Toran Liberation Army in the city of Antei, she jumped to the conclusion that she was going to be taken hostage. She agreed to "come quietly" and trust that the army was acting in good faith if they brought her the Opal.

Once the Opal was obtained in Soniere Prison and brought to the waiting Esmeralda, she willingly joined the Toran Liberation Army.

Trivia

 * Esmeralda never actually takes the Opal from you. I guess she just wanted to look at it?