What's that bead?

I find myself asking this question more often nowadays - because I need that for my blog!  Sigh.  I regret didn't pay much attention to the names of the stones that I purchased.  I bought them because I like the look, the feel when touching them and of course the price if it was affordable.

Let's look at these:

They look interesting and I know they are some kind of shell.  They resemble Abalone Shell but an expert told me they are just 'plated' Mother-of-pearl.  That didn't upset me as I did not pay the price of Abalone Shell.  Whatever...I still like them and I have made a cool necklace with it:

This is truely my design - no copycat.  Sometimes, however, I do borrow other's idea and modify it - like this cute little necklace:

This was done upon my daughter's request.  The original one which she liked very much has been badly tarnished.  I modified the design by using different type of beads and connecters and voila! It is even nicer than the original one because of the beautiful butterfly crystals!