Agate geode. Close-up of the polished face of a section through an agate-containing geode. Agate is an aggregate of different forms of silica (SiO2) within a geode. Geodes form when silica precipitates from liquid onto the inside surface of empty pockets in a host rock. Many agates consist of both chalcedony (centre),the non-crystalline variety of silica,and quartz (clear crystals),the crystalline variety,as seen in this specimen. Actual height: 90 millimetres | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Wiersma, Dirk |
Bildgröße: | 3665 px × 4850 px |
Modell-Rechte: | nicht erforderlich |
Restrictions: | - |