Melanterite is a secondary mineral, formed by the oxidation of iron ore, or sometimes copper ore.

Chemical Formula: FeSO4(7H2O)
Class: Sulfates
Hardness: 2
Coloration: White, green to blue

How to identify it/Unique Characteristics or Properties:
Melanterite is a secondary mineral, formed by the oxidation of iron ore, or sometimes copper ore. It typically forms as a green (iron) or bluish (copper) powdery coat, especially in mines. When found in larger quantities it can look quite interesting, often translucent, but dries out quickly in air and breaks down, as in the picture above.

Where to find it in…

The Northwest: S. Santiam River, OR.
Other: Russia, Italy, Germany
Past Uses: Can be used to get ore from it, but mainly is found in small quantities so not used for much.
How it was Made: It forms when iron or copper ore breaks down.
Interesting Facts: Melanterite can be dissolved in water, and precipitates out metallic copper.