Amethyst is a violet variety of quartz that has been used as a gemstone for many centuries and is a key economic resource in northern Uruguay. Geodes are hollow rock formations often with quartz ...

Any geode might make us wonder: What geologic forces form these hollows lined with crystals? But the Pulpí Geode, discovered in an abandoned Spanish mine, takes wonder to a different scale. One of 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 ...