Your Aladdin 500 is probably the one shown below, Rich. It's a chip made as a souvenir but is fairly scarce. TCR catalog is N4697 and retails in the $50-60 range. It's a standard size chip, not an oversize baccarat. There are no indications it was ever in a piece of jewelry so I don't really know why it was made. Maybe as an invited guest chip? It's from the original Aladdin and is about 20 years old.