Geode vs. Agate: What's the Difference? While both geodes and agates are stunning natural formations, they are formed in slightly different ways, which influences their appearance and structure.

Today on A Moment of Science, we’ll look at how geodes form and how they collect in such complex patterns.

The Pulpí Geode was formed in two different phases, starting six million years ago. At first percolating water dissolved the soluble limestone, creating a large cavity.

Any geode might make us wonder: What geologic forces form these hollows lined with crystals? But the Pulpí Geode, discovered in an abandoned Spanish mine, takes wonder to a different scale. One ...

The researchers discovered that the amethyst geodes formed at unexpectedly low crystallisation temperatures of just 15 to 60 °C.

Gabriela Farfan, the Smithsonian's curator of gems and minerals, answers the internet's burning questions about gemstones. Are all minerals crystals? How are diamonds cut? How do geodes form? Is ...

"It seems likely that the large geode formed in a vug (cavity) in Miocene basalt flows," said Hillman after examining photos of the geode. Gas bubbles formed in the flowing lava, which cooled ...