Tranca Mexican Geode
These Tranca Mexican Geodes are the two halves of breathtaking geodes containing the minerals Quartz, Calcite and Chalcedony. This gives the inside of the geodes a transparent to translucent, and often blue to colourless appearance.
These Geodes also show an amazing fluorescence under ultraviolet light thanks to the presence of harmless amounts of uranium in them.
Geodes are often formed as bubbles of air in lava which hardened, with minerals then depositing inside creating the amazing crystals seen.