Landesite

General Information:
 Chemical Formula:
(Mn,Mg)9Fe+++3(PO4)8(OH)3·9(H2O)
 Composition:
(Molecular Weight = 1,565.99 gm)
Magnesium 3.49 % Mg
Manganese 23.68 % Mn
Iron 10.70 % Fe
Phosphorus 15.82 % P 
Hydrogen 1.35 % H 
Oxygen 44.95 % O 
 Empirical Formula:
9(Mn2+0.75)9(Mg0.25)Fe2+3(PO4)8(OH)3·9(H2O)
 IMA Status:
Approved IMA 1976
Physical Properties:
 Cleavage:
[???] Indistinct
 Color:
brown.
 Density:
3.026
 Hardness:
3-3.5 - Calcite-Copper Penny
 Luminescence:
Non-fluorescent.
 Streak:
light brown
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