Large Sea Urchin Shells

Large Sea Urchin Shells are the hard, round outer skeletons of sea urchins, marine animals that live on the ocean floor. Although commonly called “shells,” they are technically known as tests and are made of calcium carbonate.

Sea urchins are spiny marine animals belonging to the phylum Sea Urchin. When a sea urchin dies, its spines fall away, leaving behind the beautiful patterned shell-like structure known as a test.