Unidentified Clam

[Buddym]

This polished clam shell was gifted to me recently.
It would appear that this kind of shell is sold as 'Amahong' on E-bay, but what is its scientific name?

[paul monfils]

This is a mussel shell, a member of the family Mytilidae. It is not possible to name the species, first because there are many similar species throughout most of the oceans of the world; and second, because it has been polished, so that the original color and external features of the shell have been buffed away