Working Mother of Pearl

While I have been a practicing artist for 30 years, I am a neophite
in jewelry making. Because of a serious health condition I have had
to leave my former work and have moved to a large inland lake in
rural Wisconsin. Here I have been gathering mussel shells with a rich
range of colors. Captivated by their beauty I have been dead set on
working with them to develop a line of jewelry. While the lake action
often removes a portion of the outer shell layer, much remains. Does
anyone know proper and safe practices for removing this tough layer?
Then, what are the proper tools for shaping the mother of pearl? Your
assistance will be greatly appreciated.