Many people mistakenly think that their next plate of oysters on the half-shell might contain a gem. But unlike pearls of gem quality created by pearl oysters, pearls produced by edible oysters have low luster and resemble pebbles. Edible or "true" oysters, the type most commonly eaten, are not as closely related to pearl oysters as their names imply. Both are marine bivalves with similar anatomies and modes of reproduction, but they belong to different taxonomic families.