Zemannite
![Crystal structure of zemannite.[7]](/uploads/202502/22/Zemannite_struct5124.png)
Zemannite is a very rare oxide mineral with the chemical formula Mg0.5ZnFe[TeO3]3·4.5H2O. It crystallizes in the hexagonal crystal system and forms small prismatic brown crystals. Because of the rarity and small crystal size, zemannite has no applications and serves as a collector's item.