Geodes are small rock cavities lined with crystals or minerals. They form through sedimentation, a process in which particles (solute) are suspended in fluid (solvent) and then accumulate. (Here, the ...

The geological history that led to the formation of giant crystals and a 36-foot geode has been revealed by scientists. By looking at the abandoned mine where the geode of Pulpí was found, they were ...

Amethyst geodes—some stretching 5 m long—dot the ancient lava flows of Uruguay’s Los Catalanes mining area. The geodes contain calcite, colorless quartz, and agate, another quartz mineral. Large ...

Göttingen University researcher Fiorella Arduin Rode working in open pit mine of the study area, Los Catalanes mining district, northern Uruguay. Along with Ametista do Sul in southern Brazil, these ...