Nacre

Nacre is a fancy word for something called mother of pearl. You might have seen it before, it's the stuff that looks pearly on the inside of some seashells or on the outside of pearls.

Inside those seashells, there is a special layer called the mantle. This layer makes something called "nacre" and it's what gives the seashell it's beautiful shine.

Nacre is made up of tiny, tiny plates stacked one on top of the other. Kind of like when you stack your building blocks, but even smaller. When light shines on these plates, it bounces off each one, making the seashell shiny and pearly.

Scientists have been studying nacre because it's incredibly strong and flexible. It's so strong that it's even used in some forms of body armor! Isn't that cool?

So next time you see something pearly and shiny, remember that nacre is the secret ingredient that makes it that way!