Taxonomy Search:

Gemma gemma
Image courtesy of Melissa Frey, Royal BC Museum
Gemma gemma
Taxonomic Group: Mollusks-Bivalves


Gemma gemma is commonly known as the Amethyst Gem Clam. It is native to the northwest Atlantic from southern Labrador to Venezuela, including the Bahamas, Cuba, Puerto Rico, and the Virgin Islands. It was first found outside its native range in the digestive system of a wild duck sold at a San Francisco market in 1893, and was found to be established in San Francisco Bay. Its current range extends from Elkhorn Slough to Humboldt Bay, California. It inhabits muddy-to-sandy sediments in the intertidal and shallow subtidal zone. Gemma gemma is a potential competitor with other small bivalves and with the juveniles of large native bivalves.

This is some default tab content, embedded directly inside this space and not via Ajax. It can be shown when no tabs are automatically selected, or associated with a certain tab, in this case, the first tab.


Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT (2018)
National Exotic Marine and Estuarine Species Information System.
Access Date:

Marine Invasions Lab
Smithsonian Environmental Research Center

P.O. Box 28
647 Contees Wharf Road
Edgewater, MD 21037-0028 Tel: 443 482 2200
Fax: 443 482 2380

Databases Overview| Chesapeake Bay | National Database |