Rockhounders can find all kinds of gemstones across the United States, but there are certain places where geodes can be found ...

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 ...

Forbes contributors publish independent expert analyses and insights. David Bressan is a geologist who covers curiosities about Earth. Discovered in 1999 during mining operations in the Mina Rica (the ...

People view the 12-foot tall amethyst geode from Uruguay hosted at the American Museum of Natural History in New York. Thanks to geological surveys and detailed chemical analysis, a team of ...