Vivianite
Mineral Fe3(PO4)2·8H2O
Also called Blue iron earth
Take care.
- Fades or changes in light: Keep it in the dark, out of sunlight and bright display lights.
- Fragile: Handle it gently and pack it well; it breaks or crumbles easily.
About it
Clear to green blades that darken to deep blue as the iron oxidizes, faster in light; soft and easy to split. Fine crystals come from Bolivia and Anloua in Cameroon, and it also fills fossil shells and bones.
- Type
- Mineral
- Group
- Phosphate, vivianite group
- Formula
- Fe3(PO4)2·8H2O
- Hardness (Mohs)
- 1.5–2
- Specific gravity
- 2.67–2.69
- Streak
- white, turning dark blue or brown
- Lustre
- vitreous (glassy), pearly, earthy
- Crystal system
- Monoclinic
- Colours
- colourless or pale green when fresh, darkening to blue-green, deep blue, and blue-black
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction, flexible thin plates
Typical values: real specimens vary. For more, see mindat.org.