Lovely day for a bit of rockhounding. Found agates, geodes, and the mild realization that we’re holding something older than civilization. Not bad for a river we nearly ignored.

What starts as a fun Kentucky rockhounding trip quickly turns into a series of absurd crystal reveals. Broken geodes are already scattered everywhere, but the real payoff comes when they start ...

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 ...

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 ...

Amethyst is a violet variety of quartz which 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 ...

Homo erectus may have deliberately selected rocks embedded with fossils and crystals to craft their hand axes.