Macro photograph of a cross-sectioned carnelian geode; carnelian is a variety of chalcedony, which is a variety of quartz; from Washington State Image #2897 3200 X 4800 pixels
Macro photograph of the patterns in a cut and polished piece of Zebra jasper, a variety of chalcedony (cryptocrystalline quartz) from India Image #2364 4458 X 3200 pixels
Close up of a cut and polished agate from Morocco Image #3445 4745 X 2577 pixels