#17: Chiton (Sea Snail) – The Rock-Eyed Wonder
The chiton might look like an ordinary sea snail, but its eyes are made of rock. These eyes contain aragonite, a mineral that allows it to detect changes in light and shadow, even underwater. This “rock vision” helps the chiton sense predators and react quickly.

provided by constative.com
It’s one of the most bizarre examples of how nature can turn even minerals into tools for survival.
