Geode in thin section, close-up, viewed in transmitted polarised light. A geode forms when silica (SiO2) precipitates from liquid onto the inside surf
Geode in thin section, close-up, viewed in transmitted polarised light. A geode forms when silica (SiO2) precipitates from liquid onto the inside surface of an empty pocket in a host rock. The outer layers are variegated forms of chalcedony (amorphous or non-crystalline silica), with the layers becoming more crystalline towards the centre. Here, a core of quartz (the crystalline form of silica) can be seen. The banded arrangement of crystals are a result of changes in pressure, temperature, and mineral content occurring during the formation process. Magnification: when printed 10 centimetres wide.
Size: 5186px × 4082px
Photo credit: © DIRK WIERSMA/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: amorphous, bands, chalcedony, close-, concentric, cross, cross-section, cryptocrystalline, crystal, crystalline, crystals, cut, detail, dioxide, earth, gem, gemstone, geode, geological, geology, graded, light, macrocrystal, macrocrystals, microcrystal, microcrystals, mineral, mineralogy, pattern, patterned, patterns, polarised, polarized, polished, quartz, rings, science, section, sectioned, silica, silicon, slice, stone, surface, thin, transmitted, variegated
