Mansfieldite Mineral Data

Mansfieldite Mineral Data +

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General Mansfieldite Information

Chemical Formula:

AlAsO4·2(H2O)

Composition:

Molecular Weight = 201.93 gm

Aluminum 13.36 % Al 25.25 % Al₂O₃

Arsenic 37.10 % As 56.91 % As₂O₅

Hydrogen 2.00 % H 17.84 % H₂O

Oxygen 47.54 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Al(AsO₄)·2(H₂O)

Environment:

Forms a series with scorodite.

IMA Status:

Valid Species (Pre-IMA) 1948

Locality:

Hovart Butte, Lane County, Oregon, USA. Link to MinDat.org Location Data.

Name Origin:

Named for George Rogers Mansfield (1875-1947), geologist, U. S. Geological Survey.

Mansfieldite Image

Images:

Mansfieldite

Comments: White, spherical aggregates of mansfieldite.
Location: Cap Garonne Mine, Pradet, Var, Provence-Alpes-C?te d'Azur, France. Scale: Picture size 7 mm.
© Thomas Witzke / Abraxas-Verlag

Mansfieldite Crystallography

Axial Ratios:

a:b:c =1.0327:1:0.8934

Cell Dimensions:

a = 10.08, b = 9.76, c = 8.72, Z = 8; V = 857.88 Den(Calc)= 3.13

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pcab

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

By Intensity(I/I_o): 4.36(1), 5.45(1), 3.09(0.9),

Physical Properties of Mansfieldite

Cleavage:

[201] Indistinct

Color:

White, Light gray, Reddish gray.

Density:

3.031

Diaphaniety:

Transparent to Translucent

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Mansfieldite

Gladstone-Dale:

CI meas= -0.027 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.204,KPDmeas= 0.2107,KC= 0.2051

Optical Data:

Biaxial (+), a=1.622-1.631, b=1.624-1.649, g=1.642-1.663, bire=0.0200-0.0320, 2V(Calc)=38-82, 2V(Meas)=30-68. Dispersion r < v.

Calculated Properties of Mansfieldite

Electron Density:

r_electron=3.04 gm/cc
note: r_Mansfieldite=3.13 gm/cc.

Fermion Index

Fermion Index = 0.00023
Boson Index = 0.99977

Photoelectric:

PE_Mansfieldite= 25.21 barns/electron
U=PE_Mansfieldite x r_electron= 76.59 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Mansfieldite is Not Radioactive

Mansfieldite Classification

Dana Class:

40.4.1.4 (40)Hydrated Phosphates, etc

(40.4)where A+++ XO4 · x(H2O)

(40.4.1)Dana Group

40.4.1.1 Variscite AlPO4·2(H2O) Pcab 2/m 2/m 2/m

40.4.1.2 Strengite FePO4·2(H2O) Pcab 2/m 2/m 2/m

40.4.1.3 Scorodite FeAsO4·2(H2O) Pcab 2/m 2/m 2/m

40.4.1.4 Mansfieldite AlAsO4·2(H2O) Pcab 2/m 2/m 2/m

40.4.1.5 Yanomamite In(AsO4)·2(H2O) P bca 2/m 2/m 2/m

Strunz Class:

VII/C.09-70 VII - Phosphates, Arsenates and Vanadates

VII/C - Water-bearing phosphates without unfamiliar anions. cations of medium and small size: Be and Mn, Fe, Cu, Zn, Mg

VII/C.09 - Variscite group

VII/C.09-10 Metavariscite AlPO4·2(H2O) P 2₁/n 2/m

VII/C.09-20 Phosphosiderite FePO4·2(H2O) P 2₁/n 2/m

VII/C.09-30 Kolbeckite ScPO4·2(H2O) P 2₁2₁2₁ 2 2 2

VII/C.09-35 Malhmoodite FeZr(PO4)2·4(H2O) P 2₁/c 2/m

VII/C.09-50 Variscite AlPO4·2(H2O) Pcab 2/m 2/m 2/m

VII/C.09-60 Strengite FePO4·2(H2O) Pcab 2/m 2/m 2/m

VII/C.09-70 Mansfieldite AlAsO4·2(H2O) Pcab 2/m 2/m 2/m

VII/C.09-80 Scorodite FeAsO4·2(H2O) Pcab 2/m 2/m 2/m

VII/C.09-85 Yanomamite In(AsO4)·2(H2O) P bca 2/m 2/m 2/m

VII/C.09-88 Parascorodite! FeAsO4·2(H2O) HEX ? Hex

VII/C.09-90 Koninckite FePO4·3(H2O)(?) Unk Tetra

Other Mansfieldite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Mansfieldite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 - EUROmin Project 5 -Google Images 6 -Google Scholar 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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Mansfieldite

AlAsO4·2(H2O)
Dana No: 40.4.1.4 Strunz No: VII/C.09-70
Locality:

Notes: