Hi everybody,
I just cut out a blister pearl for a customer (Abalone, Haliotis Iris) and thought it is worth showing the inside!!
You can clearly see the layers of nacre as well as what we call a "pearl factory" little blisters probably caused by a fungus growing inside.
Yes the layers are a problem when cutting out pearls, very easy to chip one of these away by accident. Here is a picture of a free form pearl (3mm). These pearls take approx. 2 years to form.