Sample of chalk, a sedimentary rock formed of calcite, a form of calcium carbonate. Chalk is formed by the gradual deposition of the shells of marine organisms over millennia. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / RHYS LEWIS & MINH TAN PHAM, AHS, DECD, UNISA |
Modell-Rechte: | nicht erforderlich |
Länge: | 33 Sekunden |
Seitenverhältnis: | 16:9 |
Restrictions: | - |