Moon Snail or Shark's Eye (also known as Necklace Shell)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: Neverita duplicata · Naticidae (Moon Snail family) · Gastropod (univalve) whole shell, globose or spherical shape
Species
Neverita duplicata (formerly Polinices duplicatus)
Shell Type
Gastropod (univalve) whole shell, globose or spherical shape
Family
Naticidae (Moon Snail family)
Size
Approximately 2 to 3 inches in diameter, which is medium-large for this species. Adults typically range from 1.5 to 3.5 inches.
Color & Pattern
Uniform glossy porcelain-white to cream coloration throughout the exterior and visible spire, likely cleaned or polished. Natural specimens often feature a brownish-gray body with a darker purple-brown callus around the umbilicus, but these appear to be standard polished white specimens or thoroughly bleached/cleaned shells.
Rarity
Common, frequently found washed ashore on sandy beaches after storms or low tides.
Habitat
Inhabitants of intertidal and shallow subtidal zones, typically found buried just beneath the surface of sandy bottoms, mudflats, and sandbars in marine environments.
Geographic Range
Western Atlantic Ocean, ranging from Massachusetts down to the Gulf of Mexico, Florida, and parts of the Caribbean.
Description
These smooth, globose, highly polished shells feature a low, flattened spire and a large, rounded body whorl. The surface is porcelain-like with faint growth lines. The aperture is large and half-moon shaped, opening to a deep interior. The overall aesthetic is clean, bulbous, and heavy for its size, giving it a classic globular look prized in coastal crafts.
Key Features
Globular or spherical shape, extremely smooth and polished surface texture, low flattened spire, large body whorl, and a characteristic half-moon shaped aperture.
Collector Value
Low to moderate commercial value. While extremely popular for shell crafts, home decor, and beginner collections due to their pleasing shape, they are too common to command high prices among serious conchologists.
Condition Notes
Good to Fine condition. The shells are intact, whole, and display a smooth, glossy surface with minimal to no visible breakage or erosion, though they may have been treated or acid-washed for decorative use.
Interesting Facts
Moon snails are predatory carnivores that drill circular holes into the shells of other bivalves using an acidic secretion and their radula to feed on the soft tissue inside. They also create distinct sand collars—structures made of sand and mucus where they lay their eggs.
Ecological Role
They act as important apex predators in benthic sandy ecosystems, helping to regulate bivalve populations. They serve as prey for various marine mammals, birds, and large fish.
Similar Species
Shark Eye (Neverita lewisii or Polinices species), which can be distinguished by specific differences in the umbilical callus size, coloration, and geographic distribution.
Beach Finding Tips
Look along sandy beaches during low tide, particularly near sandbars or mudflats. Search the surf line or look for slight bumps and disturbances in the sand that indicate a buried snail.