Kröhnkite
Mineral Na2Cu(SO4)2·2H2O
Also called Kroehnkite
Take care.
- Damaged by water: Keep it dry: don't wash it, and keep it out of damp places.
About it
Azure-blue crystals and crusts from the dry copper mines of northern Chile, especially Chuquicamata. Soluble in water, so specimens should never be washed.
- Type
- Mineral
- Group
- Sulfate, hydrated
- Formula
- Na2Cu(SO4)2·2H2O
- Hardness (Mohs)
- 2.5–3
- Specific gravity
- 2.9–2.92
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Monoclinic
- Colours
- azure blue, light blue
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction
Typical values: real specimens vary. For more, see mindat.org.