Any brilliant ideas for id of this piece?

[cheryl]

<img src="images/smiley/bye.gif" alt="" border="0" />  

Hi there,

Am hoping some brilliant person out there can figure out what kind of shell was cut down and inset into this brooch- wasn't able to id from the wonderful categories already set up.

<a href="http://www.badongo.com/pic/3896655" target="_blank"><!-- m --><a class="postlink" href="http://www.badongo.com/pic/3896655">http://www.badongo.com/pic/3896655</a><!-- m --></a>




Thanks in advance for your kind assistance,