Mountkeithite Mineral Data

General Mountkeithite Information

Chemical Formula:

(Mg,Ni)11(Fe+++,Cr)3(SO4,CO3)3.5(OH)24•11(H2O)

Composition:

Molecular Weight = 1,426.01 gm

Magnesium 18.34 % Mg 30.41 % MgO

Aluminum 1.34 % Al 2.54 % Al₂O₃

Chromium 4.01 % Cr 5.86 % Cr₂O₃

Iron 5.56 % Fe 7.95 % Fe₂O₃

Copper 0.09 % Cu 0.11 % CuO

Nickel 4.61 % Ni 5.87 % NiO

Hydrogen 3.28 % H 29.35 % H₂O

Carbon 1.02 % C 3.73 % CO₂

Sulfur 5.67 % S 14.15 % SO₃

Oxygen 56.08 % O

______ ______

100.00 % 99.98 % = TOTAL OXIDE

Empirical Formula:

Mg_10.76(OH)_26.07•10.2(H₂O)Ni_1.12Cu_0.02Fe³⁺_1.42Cr_1.1Al_0.71(SO₄)_2.52(CO₃)_1.21

Environment:

Bleached serpentinite matrix.

IMA Status:

Approved IMA 1981

Locality:

Mount Keith nickel deposit, 400 km nnw of Kalgooolie, WA, Australia. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Mountkeithite + Pronunciation

Mountkeithite Image

Images:

Mountkeithite

Comments: Pinkish mountkeithite grain in matrix.
Location: Mount Keith nickel deposit, Western Australia, Australia. Scale: Picture size 2 mm.
© Thomas Witzke / Abraxas-Verlag

Mountkeithite Crystallography

Axial Ratios:

a:c = 1:2.1074

Cell Dimensions:

a = 10.698, c = 22.545, Z = 2; V = 2,234.53 Den(Calc)= 2.12

Crystal System:

Hexagonal Space Group: Unk

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

By Intensity(I/I_o): 11.3(1), 5.63(0.8), 3.765(0.6),

Physical Properties of Mountkeithite

Cleavage:

{0001} Perfect

Color:

White, Light pink.

Density:

2.12

Habit:

Flakes - Flat, thin crystals or aggregates.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Rosette - Bundled tabular aggregates resembling rose flower petals.

Hardness:

2 - Gypsum

Luster:

Pearly

Streak:

white

Optical Properties of Mountkeithite

Gladstone-Dale:

CI meas= 0.034 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.034 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2429,KPDmeas= 0.2429,KC= 0.2514
Ncalc = 1.53

Optical Data:

Uniaxial (-), e=1.51, w=1.52, bire=0.0100.

Calculated Properties of Mountkeithite

Electron Density:

Bulk Density (Electron Density)=2.16 gm/cc
note: Specific Gravity of Mountkeithite =2.12 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Mountkeithite}= 5.12 barns/electron
U=PE_{Mountkeithite} x rElectron Density= 11.08 barns/cc.

Radioactivity:

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

Mountkeithite Classification

Dana Class:

32.04.03.01 (32)Compound Sulfates

(32.04)(hydrous) with poly-anionic formula

(32.04.03)Dana Group

32.04.03.01 Mountkeithite (Mg,Ni)11(Fe,Cr)3(SO4,CO3)3.5(OH)24•11(H2O) Unk Hex

Strunz Class:

07.DD.35 07 - SULFATES (SELENATES, TELLURATES)

07.D - Sulfates (selenates, etc.) with additional anions, with H2O

07.DD -With only medium-sized cations; sheets of edge-sharing octahedra

07.DD.35 Carrboydite (Ni,Cu)14Al9(SO4,CO3)6(OH)43•7(H2O) Unk Hex

07.DD.35 Glaucocerinite (Zn,Cu)5Al3(SO4)1.5(OH)16•9(H2O) Unk (HEX-R) Trig

07.DD.35 Honessite Ni6Fe2(SO4)(OH)16•4(H2O) R 3m 3 2/m

07.DD.35 Hydrowoodwardite! Cu1-xAlx(OH)2(SO4)x/2•n(H2O)with0<x<0.67andn>3x/2 R 3m 3 2/m

07.DD.35 Zincowoodwardite! [Zn1-xAlx(OH)2][(SO4)x/2(H2O)n] P 3- or R 3m 3

07.DD.35 Hydrohonessite Ni6Fe2(SO4)(OH)16•7(H2O) Unk Hex

07.DD.35 Motukoreaite Na2Mg38Al24(CO3)13(SO4)8(OH)108•56(H2O) R 3m 3 2/m

07.DD.35 Mountkeithite (Mg,Ni)11(Fe,Cr)3(SO4,CO3)3.5(OH)24•11(H2O) Unk Hex

07.DD.35 Shigaite Mn7Al4(SO4)2(OH)22•8(H2O) R 3 3

07.DD.35 Natroglaucocerinite! (Na,Zn,Cu)10Al6(SO4)3(OH)32•18(H2O)? Unk

07.DD.35 Wermlandite (Ca,Mg)Mg7(Al,Fe)2(SO4)2(OH)18•12(H2O) P 3c1 3 2/m

07.DD.35 Nikischerite! NaFe6Al3(SO4)2(OH)18(H2O)12 R 3 3

07.DD.35 Zincaluminite Zn6Al6(SO4)2(OH)26•5(H2O) Unk Hex

07.DD.35 Woodwardite Cu4Al2(SO4)(OH)12•2-4(H2O) Unk Hex

07.DD.35 Zincowoodwardite-3R! [Zn1BxAlx(OH)2][(SO4)x/2•n(H2O)],0.32<x<0.50,n=0.59 R 3m 3 2/m

07.DD.35 Zincowoodwardite-1T! [Zn1BxAlx(OH)2][(SO4)x/2•n(H2O)],x=0.33,n.0.96 P 3 3

Other Mountkeithite Information

References:

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

See Also:

Links to other databases for Mountkeithite :
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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Mountkeithite

(Mg,Ni)11(Fe+++,Cr)3(SO4,CO3)3.5(OH)24•11(H2O)
Dana No: 32.04.03.01 Strunz No: 07.DD.35
Locality:

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