Calcium: bone and marble
What do bones and marble have in common?
Both bone and marble are built around calcium, born in supernovae; most limestone and marble is made from the shells of ancient sea creatures.
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In three stops
Where were its atoms born?
Calcium forms in the late burning stages of massive stars and in supernova explosions.
How did it form on Earth?
Most limestone is made by living things: corals, mussels and microscopic sea creatures build their shells from calcium carbonate, and when they die the shells pile up on the sea floor and turn to rock. Heat and pressure turn limestone into marble. The white travertine terraces of Pamukkale, by contrast, form from calcium carbonate deposited by hot springs.
What did humans make of it?
Lime and cement are made from limestone. Marble from Marmara Island has been quarried since antiquity, and the Sea of Marmara takes its name from it.
Did you know?
About 99% of the calcium in your body is in your bones and teeth; an adult carries about 1 kilogram of it.