Flamebright Pendant

The Flamebright Pendant is "a pendant on a silver chain, set with a large, bright red stone", which had been passed down in Aubrey's family for generations. Aubrey initially believed that the pendant simply enhanced her long-dormant magical powers, but it was later revealed to be a tiny shard of the Great Crystal located in the heart of Sylvain City.

History
The shard was separated from the rest of the crystal sometime in the sixteenth or seventeenth century A.D. (this rough date is inferred from the "conquistador" breastplates which the Earthling invaders wore and the cannons they used to shatter the crystal, as described in Episode ??). For centuries it was passed down through Aubrey Little's family, until it came into Aubrey's mother's possession. Aubrey's mother intended to pass it on to her daughter, but it was stolen by Ned Chicane and Boyd Mosche before she could do so. For several years it languished in the back room of the Cryptonomica, before being returned to Aubrey by Ned. The shard was reunited with the rest of the Great Crystal during the Finale arc.

Trivia
Though the Great Crystal of Sylvain is repeatedly described as a vivid shade of orange, the crystal of the Flamebright Pendant is a fiery red; this discrepancy is never(?) directly explained.

The act of reuniting a magical crystal shard with its shattered whole in order to restore life to a dying planet may be an homage/reference (perhaps unintentional) to the 1982 Jim Henson film The Dark Crystal.