Dufrenite Mineral Data

Dufrenite Mineral Data +

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General Dufrenite Information

Chemical Formula:

Fe++Fe+++4(PO4)3(OH)5·2(H2O)

Composition:

Molecular Weight = 685.22 gm

Iron 40.75 % Fe 10.49 % FeO / 46.61 % Fe₂O₃

Phosphorus 13.56 % P 31.07 % P₂O₅

Hydrogen 1.32 % H 11.83 % H₂O

Oxygen 44.36 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺Fe³⁺₄(PO₄)₃(OH)₅·2(H₂O)

Environment:

Secondary mineral.

IMA Status:

Valid Species (Pre-IMA) 1833

Locality:

Anglar, Haute-Vienne, Limousin, France Link to MinDat.org Location Data.

Name Origin:

Named for Armand Small Dufrenoy (1792-1857), French mineralogist and geologist.

Synonym:

ICSD 34830

PDF 22-1143

Dufrenite Image

Images:

Dufrenite

Comments: Dark olive-greenish crystal of dufrenite on matrix.
Location: Rengersdorf, G?rlitz, Oberlausitz, Saxony, Germany. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Dufrenite Crystallography

Axial Ratios:

a:b:c =5.0409:1:2.6882

Cell Dimensions:

a = 25.84, b = 5.126, c = 13.78, Z = 4; beta = 111.2° V = 1,701.72 Den(Calc)= 2.67

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.151(1), 5.002(0.9), 12(0.9),

Crystal Structure:

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Moore P B , American Mineralogist , 55 (1970) p.135-169, Crystal chemistry of the basic iron phosphates

Physical Properties of Dufrenite

Cleavage:

[???] Perfect, [???] Distinct

Color:

Brown, Greenish brown, Green black, Dark green, Olive green.

Density:

3.2 - 3.4, Average = 3.3

Diaphaniety:

Subtranslucent to opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Hardness:

3.5-4 - Copper Penny-Fluorite

Luminescence:

Non-fluorescent.

Luster:

Silky

Streak:

green

Optical Properties of Dufrenite

Optical Data:

Biaxial (+/-), a=1.82-1.842, b=1.83-1.85, g=1.875-1.925, bire=0.0550-0.0830, 2V(Calc)=38-52, 2V(Meas)=0-90. Dispersion relatively strong.

Calculated Properties of Dufrenite

Electron Density:

r_electron=2.62 gm/cc
note: r_Dufrenite=2.67 gm/cc.

Fermion Index

Fermion Index = 0.00885
Boson Index = 0.99115

Photoelectric:

PE_Dufrenite= 12.78 barns/electron
U=PE_Dufrenite x r_electron= 33.47 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Dufrenite is Not Radioactive

Dufrenite Classification

Dana Class:

42.9.1.2 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.9)where (A)3 (XO4)2 Zq · x(H2O)

(42.9.1)Dana Group

42.9.1.1 Burangaite (Na,Ca)2(Fe,Mg)2Al10(PO4)8(OH,O)12·4(H2O) C 2/c 2/m

42.9.1.2 Dufrenite FeFe4(PO4)3(OH)5·2(H2O) C 2/c 2/m

42.9.1.3 Natrodufrenite Na(Fe,Fe)(Fe,Al)5(PO4)4(OH)6·2(H2O) C 2/c 2/m

Strunz Class:

VII/D.11-110 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of medium size: Cu, Zn, Mn, Al, Fe

VII/D.11 - Strunzite series

VII/D.11-10 Ferrostrunzite FeFe2(PO4)2(OH)2·6(H2O) P 1,P1 Tri

VII/D.11-20 Strunzite MnFe2(PO4)2(OH)2·6(H2O) P1 1

VII/D.11-30 Ferristrunzite FeFe2(PO4)2(OH)3·5(H2O) P1,P 1 Tri

VII/D.11-40 Bermanite MnMn2(PO4)2(OH)2·4(H2O) P 2₁ 2

VII/D.11-50 Cacoxenite (Fe,Al)25(PO4)17O6(OH)12·75(H2O) P 6/mmm 6/m 2/m 2/m

VII/D.11-60 Tinticite Fe5(PO4,VO4)4·7(H2O) P1 1

VII/D.11-70 Beraunite FeFe5(PO4)4(OH)5·4(H2O) C 2/c 2/m

VII/D.11-71 Oxiberaunite* (Fe,Mn)Fe5(PO4)4O(OH)4·6(H2O) Mono

VII/D.11-90 Souzalite (Mg,Fe)3(Al,Fe)4(PO4)4(OH)6·2(H2O) P1,P 1 Tri

VII/D.11-100 Gormanite Fe3Al4(PO4)4(OH)6·2(H2O) P1,P 1 Tri

VII/D.11-110 Dufrenite FeFe4(PO4)3(OH)5·2(H2O) C 2/c 2/m

VII/D.11-120 Burangaite (Na,Ca)2(Fe,Mg)2Al10(PO4)8(OH,O)12·4(H2O) C 2/c 2/m

VII/D.11-130 Natrodufrenite Na(Fe,Fe)(Fe,Al)5(PO4)4(OH)6·2(H2O) C 2/c 2/m

VII/D.11-135 Ercitite! Na(Mn,Fe)(PO4)(OH)·2(H2O) P 2₁/n 2/m

VII/D.11-140 Kidwellite Na(Fe,Cu)9x(PO4)6(OH)11·3(H2O) P 2/c 2/m

VII/D.11-150 Meurigite! KFe7(PO4)5(OH)7·8(H2O) C 2,Cm,C 2/m Mono

Other Dufrenite Information

References:

NAME( Dana7) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

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Dufrenite

Fe++Fe+++4(PO4)3(OH)5·2(H2O)
Dana No: 42.9.1.2 Strunz No: VII/D.11-110
Locality:

Notes: