Set of 4 Agate Geodes
A geode is a natural rock with an internal cavity lined with crystals. Amethyst, calcite and agate tend to be the most popular geodes. Until a rock is broken open it's not possible to know what's inside.
The size of these miniature agate geodes varies from 3.4 to 5.5 centimetres (length). They're unpolished and come from South Africa.
Most agates being enjoyed today began forming many millions of years ago. Its formation is surprisingly complicated and has never been studied in real-time from start to finish.