General Information:
Chemical Formula:
(Fe++3-x,Fe+++x)(PO4)2(OH)x·8-x(H2O), x=0.5
Composition:
(Molecular Weight = 501.10 gm)
Iron 33.43 % Fe
Phosphorus 12.36 % P
Hydrogen 3.12 % H
Oxygen 51.09 % O
Empirical Formula:
Fe2+2.5Fe3+0.5(PO4)2(OH)0.5·7.5(H2O)
Environment:
Oxidized and dehydrated compared to vivianite.
IMA Status:
Approved IMA 1974
Locality:
Big Chief pegmatite, Glendale, Pennington County, South Dakota, USA.
Name Origin:
Named to reflect the relationship with vivianite.
Physical Properties:
Cleavage:
[110] Perfect
Color:
leek green, gray green, or reddish brown.
Density:
2.69
Diaphaniety:
Opaque to translucent
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Striated - Parallel lines on crystal surface or cleavage face.,
Hardness:
1.5-2 - Talc-Gypsum
Luster:
Sub Metallic
Streak:
yellowish brown
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