Geodes, crystals bursting out of a rocky shell ... as underground temps quickly cool. Tours of the cave are packaged for $13 (adults) or $8 (children aged 6 to 11) with a wine cellar tour and ...

Geodes are hollow rock formations often with quartz crystals, such as amethyst, inside. Amethyst geodes in Uruguay have been found in cooled lava flows, which date from the original breakup of the ...