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Ever thought putting in your contacts every morning was a pain? New research from the University of California shows that tiny mollusks have a sort of contacts of their own, made from rock.

Well, not rock per se; but this two inch long mollusk known as a Lined Chiton, actually has eyes made out of the rocky substance called calcium carbonate. You marine biology buffs might recognize this as the hard skeleton from which all living coral reef grow (or you late-night hot wing lovers might know it as the main ingredient in those chalky antacids). So, how can these Chitons see with rocks?

Rather than using lenses made of proteins, as is standard in the animal kingdom, Chitons can actually sense changes in light, size, and shape of objects by focusing with aragonite (calcium carbonate) lenses. Although scientists discovered many years ago the dozens of eye structures on Chitons were able to sense light, they remained unaware of what they were actually made of and how well they could see. 

“Turns out they can see objects, though probably not well,” explained Daniel Speiser, a member of the University of California research team in Santa Barbara.

To put their sight abilities in context, the study found out that human sight is approximately a thousand times sharper then our mollusk friends. And while the Chitons may not have a career as sharpshooters, this limited eyesight is critical in defending against predators. Even more surprisingly, although fossils of Chitons date back to around 500 million years, evidence of eye-abled Chitons appeared only 25 million years ago- the most recent to evolve in animals.