PASCAL GOETGHELUCK / SCIENCE PHOTO LIBRARY PASCAL GOETGHELUCK / SCIENCE PHOTO LIBRARY
Crystal geode. Palaeontologist holding a geode found in a rock on a sea-shore. A geode is a concretion, an irregular or ball-shaped object created when minerals fill a cavity in rock. Geodes form in different ways in different rock types. Here the geode formed from a cavity left by a fossilised ball of algae.
Model release not available. Property release not required.