Can somebody tell me what these are called?!

[argon 3]

I bought this thing this weekend... even though I didn't absolutely love the colour (though, it'll probably look nice when the light hits it). If you can't tell from the pic, its a 'mobile' with those flat, iridescent-y shells.

I have this idea that I'd like to make my own, with shells the colour *I* want them to be. But I have no idea what those shells are called, to look up somewhere online to buy them. I can't just say 'sea shells', cause I'm not getting the results I want. Anyone have any clue?

(sorry it's sideways!)

[Devana 0]

I think those are called cadiz shells.

[Carlene 12]

Close....they are capiz shells.