Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance ...

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 ...

Göttingen University researcher Fiorella Arduin Rode working in open pit mine of the study area, Los Catalanes mining district, northern Uruguay. Along with Ametista do Sul in southern Brazil, these ...