Rinoa does not wear a lot of jewerly, but the ones she does wear are very important to her.

Like Squall, Rinoa wears a necklace, this necklace favours a small chain as a normal necklace, but stronger with many different aspects. The necklace beholds one ring wit no special gravings on it. It is not stated from who this ring is, but many fans believe this ring belongs to her mother, since she grabs it whenever she feels unsure.

Later in the game, thanks to Zell, Rinoa get's a hold on Squall's ring which is explained here. Like the ring of her mother, Squall's ring is also very important, since even though she believes in everyone, her hopes lies in the hands of the memories of her mother and Squall.

During the SeeD graduation ball, we first meet Rinoa in her special ball outfit, here she also wears a special jewerly which she does not wear throughout the rest of the game, due to her arm-warmers. She wears a bracelet around her right wrist, also in silver. Since that the bracelet is difficult to view during the scene, but I think it has small diamonds in it, because I think Rinoa likes wearing expensive stuff.