A geode observed in thin section, photographed with transmitted, polarized light, reveals the details of the precipitation and crystallization of silica in a rock void. Geodes form when chalcedony (silica, SiO2) precipitates from liquids percolating inside an empty void or crack in a host rock. The peripheral layers here formed are amorphous to sub-crystalline silica, while the core is made up of crystalline quartz. Actual width is 44 mm | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Wiersma, Dirk |
Bildgröße: | 4972 px × 3552 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |