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.

Name Pronunciation:

Mansfieldite + Pronunciation

Mansfieldite Image

Images:

Mansfieldite

Comments: White, spherical aggregates of mansfieldite.
Location: Cap Garonne Mine, Pradet, Var, Provence-Alpes-Côte 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),

Crystal Structure:

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Harrison W T A , Acta Crystallographica, Section C , 56 (2000) p.e421-e421, Synthetic mansfieldite, AlAsO4*2H2O, Locality: synthetic, Sample: T = 298 K

Physical Properties of Mansfieldite

Cleavage:

{201} Indistinct

Color:

White, Light gray, Reddish gray.

Density:

3.031

Diaphaneity:

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
Ncalc = 1.62 - 1.64

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:

Bulk Density (Electron Density)=3.04 gm/cc
note: Specific Gravity of Mansfieldite =3.13 gm/cc.

Fermion Index:

Fermion Index = 0.0002311828
Boson Index = 0.9997688172

Photoelectric:

PE_Mansfieldite= 25.21 barns/electron
U=PE_Mansfieldite x rElectron Density= 76.59 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Mansfieldite is Not Radioactive

Mansfieldite Classification

Dana Class:

40.04.01.04 (40)Hydrated Phosphates, etc

(40.04)where A+++ XO4 · x(H2O)

(40.04.01)Variscite Group

40.04.01.01 Variscite AlPO4•2(H2O) Pcab 2/m 2/m 2/m

40.04.01.02 Strengite FePO4•2(H2O) Pcab 2/m 2/m 2/m

40.04.01.03 Scorodite FeAsO4•2(H2O) Pcab 2/m 2/m 2/m

40.04.01.04 Mansfieldite AlAsO4•2(H2O) Pcab 2/m 2/m 2/m

40.04.01.05 Yanomamite In(AsO4)•2(H2O) P bca 2/m 2/m 2/m

Strunz Class:

08.CD.10 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CD -With only medium-sized cations, RO4:H2O = 1:2

08.CD.10 Strengite FePO4•2(H2O) Pcab 2/m 2/m 2/m

08.CD.10 Mansfieldite AlAsO4•2(H2O) Pcab 2/m 2/m 2/m

08.CD.10 Variscite AlPO4•2(H2O) Pcab 2/m 2/m 2/m

08.CD.10 Scorodite FeAsO4•2(H2O) Pcab 2/m 2/m 2/m

08.CD.10 Yanomamite In(AsO4)•2(H2O) P bca 2/m 2/m 2/m

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 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - WWW-MINCRYST

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Print or Cut-and-Paste your Mansfieldite Specimen Label here :

Mansfieldite

AlAsO4•2(H2O)
Dana No: 40.04.01.04 Strunz No: 08.CD.10
Locality:

Notes: