Oysters

Pinctada is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae, the pearl oysters. These oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl". Pearl oysters are not closely related to either the edible oysters of family Ostreidae or the freshwater pearl mussels of the families Unionidae and Margaritiferidae.

Hammer Oysters and Pacific Spiny Oysters are not closely related to true oysters (family Ostreidae); however, they do share some habits such as cementing themselves to rocks rather than attaching themselves by a byssus. The two halves of their shells are joined with a ball-and-socket type of hinge, rather than with a toothed hinge as is more common in other bivalves. They also still retain vestigial anterior and posterior auricles ("ears", triangular shell flaps) along the hinge line, a characteristic feature of scallops, though not of oysters.

As is the case in all scallops, Spondylus spp. have multiple eyes around the edges of their mantle, and they have relatively well-developed nervous systems. Their nervous ganglia are concentrated in the visceral region, with recognizable optic lobes connected to the eyes.

The Shell you receive may not look exactly like the image.  No two are alike.