The three-meter tall amethyst geode - a hollow rock filled with amethyst crystals - is the main attraction at the Crystal Caves at Atherton, southwest of Cairns. But it's now missing a bit after a ...

Amethyst geodes in Uruguay have been found in cooled lava flows, which date from the original breakup of the supercontinent Gondwana around 134 million years ago. However, their formation has ...