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 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 ...

On a visit to Tucson, relatives took me to a gem and mineral show where we saw a collection of geodes. Ordinary on the outside; beautiful on the inside. Will you please tell us how they are formed and ...