Fossil shell of Pithocerithium rubiginosum (height is 1.5 cm) from the Miocene sediments of Nexing in Austria (left) and isolated reddish polyene pigments on calcium fluoride disc (diameter of ...

The recent shells retain the organic material that give the shells ... The process may be aragonite crystallizing to calcite, as in fossil snails, or it may be the growth of larger crystals of an ...

These items included two 56-million-year-old jaw bones from an ancient horse and an early ancestor of modern primates, as ...