Where Do Seashells Come From?

Watch how mollusks extract minerals from the ocean to build their shells layer by layer over a lifetime.

Old Shell Growth
Active Growth Edge
The Mantle (Organ)
Calcium Carbonate Ions

Biological Simulator

The Mantle's Work

The mollusk is young. Its fleshy mantle is absorbing calcium and carbonate from the water and food, combining them into crystals to build the leading edge of its new home.