Wow, thanks so far for your input!
I'm searching e-bay for the perfect keishi pearl, still waiting to find one with great orient.
The 'cut in half'-pearls are a great idea! I will do my best to incude those.
I'm working hard on the oyster and mussel shells. A Pinctada Maxima is in the mail, and I will get a mussel next month (I'm already starting a small anthill in my garden to get it cleaned

). Now I just need to find an akoya oyster.
I already have many different shapes of freshwater pearls, so that part is covered.
Sheila