He says that part of the reason the Marie Antoinette pearl is worth so much is because it's a natural pearl, which brings us to one quality that determines a pearl's value. Natural versus cultured.

Natural pearls are usually white or cream in color, while cultured pearls come in a range of hues, including pink, blue, ...

Pearls are made by marine oysters and freshwater mussels as a natural defence against an irritant such as a parasite entering their shell or damage to their fragile body. The oyster or mussel slowly ...