What kind of Trochidae is it?

[vaparker]

Thank you for your help.  I did suspect it had been altered from its natural state.  

I have a collection that was my dad's (he used them for teaching biology). It includes large pieces of several different kinds of coral, a few abalone shells, conchs, whelks, and many that I have no idea what they are.  Do you know of anyone in Virginia or North Carolina who might be willing to help me identify these things and tell me if any are of real value? I can't really devote the time necessary to id them, nor do I know enough to be certain of my identification. I could really use some help.
Thanks again.