ELI5 Pearls - how does a grain of sand make such treasure?

Explain Like I'm 5: Bite sized answers to stuff you should know about - in a mini podcast by ELI5 Explain Like I'm Five Podcast

What makes a pearl so mesmerizing, and what is it really? What exactly is a pearl made of, and how does it form inside a mollusk? Can a grain of sand truly cause a perfect pearl? What's the difference between a natural p...View more