Melanterite
Mineral FeSO4·7H2O
Also called Copperas and Green vitriol
Take care.
- Damaged by water: Keep it dry: don't wash it, and keep it out of damp places.
- Breaks down in damp air: Keep it dry and in steady humidity; some crumble or rot as they take on moisture.
About it
Pale green crusts and stalactites that grow where pyrite and marcasite decay, in damp mines and on rotting pyrite in collections. Dissolves in water and crumbles to yellowish powder as it dries.
- Type
- Mineral
- Group
- Sulfate, melanterite group
- Formula
- FeSO4·7H2O
- Hardness (Mohs)
- 2
- Specific gravity
- 1.89–1.9
- Streak
- white
- Lustre
- vitreous (glassy), silky
- Crystal system
- Monoclinic
- Colours
- green, blue-green, greenish white, yellowish when altered
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.