amethyst gem clam

{{Short description|Species of bivalve}}

{{Speciesbox

| name = Amethyst gem clam

|image=Gemma gemma (I0435) (14453187255).jpg

| image_caption =Gemma gemma shell

| taxon = Gemma gemma

| parent_authority = Deshayes, 1853

| authority = (Totten, 1834)

| synonyms = Gemma purpurea Lea, 1842

}}

The amethyst gem clam (Gemma gemma) is species of very small saltwater clam, a marine bivalve mollusk in the family Veneridae, the Venus clams.

It is a small species, reaching a length of only 5 mm.{{cite journal |author=Sellmer, G P |year=1967 |title=Functional morphology and ecological life history of the gem clam, Gemma gemma (Eulamellibranchia: Veneridae) |journal=Malacologia |volume=5 |pages=37–233}} The shell color is whitish or grayish, suffused with purple on both outer and inner surfaces.

The species is native to the Atlantic coast of North America, from Labrador to Texas,{{cite web|url=http://www.issg.org/database/species/ecology.asp?si=1146&fr=1&sts=sss&lang=EN|title=Gemma gemma (mollusc) |author = Global Invasive Species Database |access-date = 11 February 2011}} but it is now also found as an introduced species in some locations on the Pacific coast.{{cite journal |title=Climate change, species range limits and body size in marine bivalves |author=Kaustuv R, D Jablonski & J W Valentine |journal=Ecology Letters |volume=4 |pages=366–370 |url=http://geosci.uchicago.edu/pdfs/jablonski/ELett2001.pdf |access-date = 11 February 2011 | doi=10.1046/j.1461-0248.2001.00236.x | year=2001 |issue=4|bibcode=2001EcolL...4..366K }}