A brooch that has a blue stone, which appears to have been which appears to have been broken in two, set inside of it.
The Sapphire Brooch is a broken charm shared by Orlha and her transdimensional sister Tia. In actuality, both fragments are part of a Blue Brooch. Orlha gives her piece to Serge while he is still in Lynx's form on condition that he show her the brooch once he returns to his human body. After Orlha joined the party and located Tia in Guldove (Home World), Tia revealed that the split parts of the gem originated from either world and contain the prayers of their mother and father. Orlha and Tia then seal their pieces to form the Blue Brooch.
Theory and Analysis
That the fragments of the brooch originate from differnet worlds is another aspect of the Tia / Orlha dimensional discrepancy. Tia and Orlha are described as sisters, but also seem to be the dimensional equivalent of each other (as if they were the same person). It is unknown how one contacted the other across the dimensions after the split, or what their true relation is.
From: Key Items (Chrono Cross)