_:n0b5dca8e359b42b286813e85302a28acxb0
<http://schema.org/description>
"Belemnites were squid-like creatures that became extinct at then end of the Mesozoic Era (66 million years ago). One of the main differences between belemnites and modern squids is that belemnites had hard internal parts, This rod-like structure is called a rostrum, and was originally formed from calcium carbonate. Here, the carbonate has been replaced by precious opal."
<https://artsandculture.google.com/asset/uQEgn36LEjg16g?childAssetId=lQFhpvFtj796Pw>