Bílinite
Bílinite is an iron sulfate mineral. It is a product of the oxidation of pyrite in water. It is an acidic mineral that has a pH of less than 3 and is harmful to the environment when it comes from acid rock drainage.
Bílinite was first discovered near Bílina, Czech Republic which is why the mineral was named 'bílinite'. This mineral possibly occurs on Mars.
Composition
The weight percent oxide is as follows:| Oxide | Composition |
| SO3 | 33.78 |
| Fe2O3 | 16.84 |
| FeO | 7.58 |
| H2O | 41.8 |
| Total | 100 |