Natropharmacosiderite Mineral Data

General Natropharmacosiderite Information

Chemical Formula:

(Na,K)2Fe+++4(AsO4)3(OH)5•7(H2O)

Composition:

Molecular Weight = 902.63 gm

Potassium 2.17 % K 2.61 % K₂O

Sodium 4.33 % Na 5.84 % Na₂O

Iron 24.75 % Fe 35.38 % Fe₂O₃

Arsenic 24.07 % As 36.92 % As₂O₅

Hydrogen 2.14 % H 19.16 % H₂O

Oxygen 42.54 % O

______ ______

100.00 % 99.91 % = TOTAL OXIDE

Empirical Formula:

Na_1.7K_0.5Fe³⁺₄(AsO₄)_2.9(OH)_5.6•6.8(H₂O)

Environment:

Found on a museum specimen, presumably an alteration product of arsenopyrite.

IMA Status:

Approved IMA 1985

Locality:

Marda, Western Australia. Link to MinDat.org Location Data.

Name Origin:

Named for the sodium in the composition and its relationship to pharmacosiderite.

Synonym:

Sodium pharmacosiderite - Renamed to Natropharmacosiderite by Mineralogical Record, v39 (2008), p131

Natropharmacosiderite Crystallography

Cell Dimensions:

a = 8.012, Z = 1; V = 514.31 Den(Calc)= 2.91

Crystal System:

Isometric - Hextetrahedral H-M Symbol (4 3m) Space Group: P 43m

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

By Intensity(I/I_o): 7.99(1), 3.27(0.8), 2.831(0.6),

Physical Properties of Natropharmacosiderite

Cleavage:

{001} Imperfect

Color:

Pale green, Dull orange.

Density:

2.79

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Cubic Crystals - Occurs as cubic shaped crystals.

Hardness:

3 - Calcite

Luster:

Vitreous (Glassy)

Optical Properties of Natropharmacosiderite

Gladstone-Dale:

CI meas= 0 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.041 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2423,KPDmeas= 0.2527,KC= 0.2526
Ncalc = 1.7 - 1.74

Optical Data:

Isotropic, n=1.705.

Calculated Properties of Natropharmacosiderite

Electron Density:

Bulk Density (Electron Density)=2.71 gm/cc
note: Specific Gravity of Natropharmacosiderite =2.79 gm/cc.

Fermion Index:

Fermion Index = 0.0054567043
Boson Index = 0.9945432957

Photoelectric:

PE_{Natropharmacosiderite}= 23.78 barns/electron
U=PE_{Natropharmacosiderite} x r_electron= 64.55 barns/cc.

Radioactivity:

GRapi = 30.39 (Gamma Ray American Petroleum Institute Units)
Concentration of Natropharmacosiderite per GRapi unit = 3.29 (%)

Estimated Radioactivity from Natropharmacosiderite - barely detectable

Natropharmacosiderite Classification

Dana Class:

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

(42.08)where (AB)7 (XO4)4 Zq � x(H2O)

(42.08.01)Pharmacosiderite Group

42.08.01.01 Pharmacosiderite KFe4(AsO4)3(OH)4•6-7(H2O) I 43m 4 3m

42.08.01.02 Alumopharmacosiderite KAl4(AsO4)3(OH)4•6•5(H2O) P 43m 4 3m

42.08.01.03 Bariopharmacosiderite BaFe4(AsO4)3(OH)5•5(H2O) I 42m 4 2m

42.08.01.04 Barium-alumopharmacosiderite? BaAl4(AsO4)3(OH)5•5(H2O) P 43m ? 4 3m

42.08.01.05 Natropharmacosiderite (Na,K)2Fe4(AsO4)3(OH)5•7(H2O) P 43m 4 3m

Strunz Class:

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

08.D - Phosphates, etc

08.DK -With large and medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1

08.DK.10 Alumopharmacosiderite KAl4(AsO4)3(OH)4•6•5(H2O) P 43m 4 3m

08.DK.10 Barium-alumopharmacosiderite? BaAl4(AsO4)3(OH)5•5(H2O) P 43m ? 4 3m

08.DK.10 Bariopharmacosiderite BaFe4(AsO4)3(OH)5•5(H2O) I 42m 4 2m

08.DK.10 Barium-zinc-alumopharmacosiderite* (Ba,K)0.5(Zn,Cu)0.5(Al,Fe)4(AsO4)3•5(H2O) I 42m 4 2m

08.DK.10 Pharmacosiderite KFe4(AsO4)3(OH)4•6-7(H2O) I 43m 4 3m

08.DK.10 Natropharmacosiderite (Na,K)2Fe4(AsO4)3(OH)5•7(H2O) P 43m 4 3m

Other Natropharmacosiderite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Natropharmacosiderite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Natropharmacosiderite

(Na,K)2Fe+++4(AsO4)3(OH)5•7(H2O)
Dana No: 42.08.01.05 Strunz No: 08.DK.10
Locality:

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