Ernstite Mineral Data

General Ernstite Information

Chemical Formula:

(Mn++1-xFe+++x)Al(PO4)(OH)2-xOx

Composition:

Molecular Weight = 210.86 gm

Manganese 13.03 % Mn 16.82 % MnO

Aluminum 12.80 % Al 24.18 % Al₂O₃

Iron 13.24 % Fe 18.93 % Fe₂O₃

Phosphorus 14.69 % P 33.66 % P₂O₅

Hydrogen 0.72 % H 6.41 % H₂O

Oxygen 45.53 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺_0.5Fe³⁺_0.5Al(PO₄)(OH)_1.5O_0.5

Environment:

Oxidation product of eosphoite in granitic pegmatite.

IMA Status:

Approved IMA 1970

Locality:

Daib-East farm, Karibib, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named for Theodor K. A. Ernst (1904-), mineralogist, University of Erlangen, Germany.

Name Pronunciation:

Ernstite

Ernstite Image

Images:

Ernstite Schoonerite

Comments: 1 mm honey brown, acicular, radial sprays of ernstite with light green fibrous schoonerite and apatite in siderite.
Location: White Cap mine, Pennington County., South Dakota. Scale: Picture size 3 mm.
© Tom Loomis / Dakota Matrix

Ernstite Crystallography

Axial Ratios:

a:b:c =1.326:1:0.6639

Cell Dimensions:

a = 13.92, b = 10.497, c = 6.969, Z = 8; beta = 90.37° V = 1,018.28 Den(Calc)= 2.75

Crystal System:

Monoclinic Space Group: C 2/c or Cc

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

By Intensity(I/I_o): 2.829(1), 2.836(0.8), 2.438(0.5),

Physical Properties of Ernstite

Cleavage:

{010} Good, {100} Good

Color:

Yellow brown.

Density:

3.07

Diaphaneity:

Translucent

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

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

Hardness:

3-3.5 - Calcite-Copper Penny

Optical Properties of Ernstite

Gladstone-Dale:

CI meas= -0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.128 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2552,KPDmeas= 0.2286,KC= 0.2262
Ncalc = 1.62 - 1.69

Optical Data:

Biaxial (-), a=1.678, b=1.706, g=1.721, bire=0.0430, 2V(Calc)=70, 2V(Meas)=74. Dispersion r > v.

Pleochroism (x):

yellow brown.

Pleochroism (y):

red brown.

Pleochroism (z):

pale yellow.

Calculated Properties of Ernstite

Electron Density:

Bulk Density (Electron Density)=3.00 gm/cc
note: Specific Gravity of Ernstite =3.07 gm/cc.

Fermion Index:

Fermion Index = 0.0030271031
Boson Index = 0.9969728969

Photoelectric:

PE_Ernstite= 8.34 barns/electron
U=PE_Ernstite x rElectron Density= 25.02 barns/cc.

Radioactivity:

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

Ernstite Classification

Dana Class:

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

(42.07)where (AB)5 (XO4)3 Zq ï¿½ x(H2O)

(42.07.01)Childrenite Group

42.07.01.01 Childrenite FeAl(PO4)(OH)2•(H2O) Bba2 mm2

42.07.01.02 Eosphorite MnAl(PO4)(OH)2•(H2O) Bbam 2/m 2/m 2/m

42.07.01.03 Ernstite (Mn1-xFex)Al(PO4)(OH)2-xOx C 2/c or Cc Mono

42.07.01.04 Sinkankasite H2MnAl(PO4)2(OH)•6(H2O) P1 1

Strunz Class:

08.DD.20 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DD -With only medium-sized cations, (OH, etc.):RO4 = 2:1

08.DD.20 Childrenite FeAl(PO4)(OH)2•(H2O) Bba2 mm2

08.DD.20 Eosphorite MnAl(PO4)(OH)2•(H2O) Bbam 2/m 2/m 2/m

08.DD.20 Ernstite (Mn1-xFex)Al(PO4)(OH)2-xOx C 2/c or Cc Mono

Other Ernstite Information

References:

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

See Also:

Links to other databases for Ernstite :
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

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

Ernstite

(Mn++1-xFe+++x)Al(PO4)(OH)2-xOx
Dana No: 42.07.01.03 Strunz No: 08.DD.20
Locality:

Notes:

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