Spheniscidite Mineral Data

General Spheniscidite Information

Chemical Formula:

(NH4,K)(Fe+++,Al)2(PO4)2(OH)•2(H2O)

Composition:

Molecular Weight = 413.28 gm

Potassium 3.78 % K 4.56 % K₂O

Aluminum 5.22 % Al 9.87 % Al₂O₃

Iron 22.97 % Fe 32.84 % Fe₂O₃

Phosphorus 14.99 % P 34.35 % P₂O₅

Hydrogen 0.59 % H - % Calc as (NH₄)₂O

Hydrogen 1.63 % H 14.60 % H₂O

Nitrogen 2.03 % N 3.78 % (NH₄)₂O

Oxygen 48.78 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

(NH₄)_0.6K_0.4Fe³⁺_1.7Al_0.8(PO₄)₂(OH)_2.5ï¿½2.1(H₂O)

Environment:

Formed by interaction of phosphate solutions derived from quano with micacous and chloritic minerals in soil under a penguin rookery.

IMA Status:

Approved IMA 1986

Locality:

On Elephant Island, South Shetland Islands, about 800 km southeast of Cape Horn, British Antarctic Territory, Antartica. Link to MinDat.org Location Data.

Name Origin:

Named for "Sphenisciformes," the Latin order name or penguins.

Name Pronunciation:

Spheniscidite + Pronunciation

Synonym:

ICSD 75229

PDF 41-593

Spheniscidite Crystallography

Axial Ratios:

a:b:c =1.0124:1:1.0072

Cell Dimensions:

a = 9.75, b = 9.63, c = 9.7, Z = 4; beta = 102.567° V = 888.94 Den(Calc)= 3.09

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/n

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

By Intensity(I/I_o): 6.79(1), 5.99(0.9), 3.05(0.45),

Physical Properties of Spheniscidite

Color:

Brown.

Density:

2.71

Diaphaneity:

Transparent to Translucent

Habit:

Selvage - As a reaction rim, surrounding the host mineral.

Hardness:

1-1.5 - Talc or a little harder

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Spheniscidite

Gladstone-Dale:

CI meas= -0.053 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.077 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2265,KPDmeas= 0.2583,KC= 0.2453
Ncalc = 1.66 - 1.76

Optical Data:

Biaxial (?), b=1.7

Calculated Properties of Spheniscidite

Electron Density:

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

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Spheniscidite}= 7.99 barns/electron
U=PE_{Spheniscidite} x r_electron= 21.63 barns/cc.

Radioactivity:

GRapi = 54.53 (Gamma Ray American Petroleum Institute Units)
Concentration of Spheniscidite per GRapi unit = 1.83 (%)

Estimated Radioactivity from Spheniscidite - barely detectable

Spheniscidite Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.06)Leucophosphite Group

42.11.06.01 Leucophosphite KFe2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

42.11.06.02 Tinsleyite KAl2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

42.11.06.03 Spheniscidite (NH4,K)(Fe,Al)2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

Strunz Class:

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

08.D - Phosphates, etc

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

08.DH.10 Leucophosphite KFe2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

08.DH.10 Spheniscidite (NH4,K)(Fe,Al)2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

08.DH.10 Tinsleyite KAl2(PO4)2(OH)•2(H2O) P 2₁/n 2/m

Other Spheniscidite 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 Spheniscidite :
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 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Spheniscidite

(NH4,K)(Fe+++,Al)2(PO4)2(OH)•2(H2O)
Dana No: 42.11.06.03 Strunz No: 08.DH.10
Locality:

Notes:

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