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.

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 ...