Researchers from the University of Göttingen have investigated an intriguing geological phenomenon in Uruguay. These scientists are trying to uncover the mysteries behind the formation of amethyst ...

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 ...

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 ...

Sparkling hollows filled with lustrous crystals, dubbed geodes, are often perceived as small objects that can fit comfortably on a bookshelf. But some are more like gigantic cathedrals filled with a ...

Since at least December 2017, a photograph of an impressively tall geode has bounced around the blogophere, almost always credited to a company called Nowar Minerals Inc. and accompanied by the ...