Please look at Microshells homepage for details. I removed sand with a sieve opening of 1mm and a lot of shells also fell through. He requested Dr. Tadashige HABE to identify them. There are shells of several species the names became clear only with difficulty.
Musical sand is well sorted and washed clean by the sea.
The sand within the shells was washed out completely by a special vibration apparatus. Even the same species have different designs. They are competing with fashion. They hide their designs with algae when alive. They show their beautiful designs to us when they die and are thrown onto a beach.