Help identifying these little guys...

[dizarray]

Thanks - I knew I had messed up the link somehow.
And I haven't actually "collected" any as of yet. I photographed them in Mattapoisett, Massachusetts, this past weekend. There were TONS washed up on shore. From a standing position, they look like light purple pebbles or something. It's only when you get down close to them that you see they are tiny little shells.