Here’s Why Seashells Don’t Have the Consistency of Chalk

 

Chalk and seashells are made of the same thing: calcium carbonate. Shells are stronger because they have trapped proteins inside, and scientist had thought that these proteins were trapped like flies in amber. It turns out it’s way more organized than that.

http://gizmodo.com/heres-why-seashells-dont-have-the-consistency-of-chalk-1751922959