Motukoreaite Mineral Data

General Motukoreaite Information

Chemical Formula:

Na2Mg38Al24(CO3)13(SO4)8(OH)108•56(H2O)

Composition:

Molecular Weight = 6,011.40 gm

Sodium 0.76 % Na 1.03 % Na₂O

Magnesium 15.36 % Mg 25.48 % MgO

Aluminum 10.77 % Al 20.35 % Al₂O₃

Hydrogen 3.69 % H 32.97 % H₂O

Carbon 2.60 % C 9.52 % CO₂

Sulfur 4.27 % S 10.65 % SO₃

Oxygen 62.55 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂Mg₃₈Al₂₄(CO₃)₁₃(SO₄)₈(OH)₁₀₈•56(H₂O)

Environment:

Rim cement in volcanic breccias in weathered submarine environments.

IMA Status:

Approved IMA 1977

Locality:

Brown's Island, (Motukorea) within Waitemata Harbor, New Zealand. Link to MinDat.org Location Data.

Name Origin:

Named for the Maori name for the locality (Motukorea - "island of the cormorants.").

Name Pronunciation:

Motukoreaite + Pronunciation

Synonym:

ICSD 29523

PDF 41-1380

Motukoreaite Image

Images:

Motukoreaite

Comments: Colorless, tabular crystals of motukoreaite.
Location: Stradnerkogel Quarry, Wilhelmsdorf, Styria, Austria. Scale: Picture size 1.5 mm.
© Thomas Witzke / Abraxas-Verlag

Motukoreaite Crystallography

Axial Ratios:

a:c = 1:3.65351

Cell Dimensions:

a = 9.172, c = 33.51, Z = 0.4; V = 2,441.37 Den(Calc)= 1.64

Crystal System:

Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3m

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

By Intensity(I/I_o): 11.32(1), 3.72(0.7), 5.58(0.6),4.59(0.6), 2.58(0.4), 1.924(0.3), 2.39(0.3),

Physical Properties of Motukoreaite

Cleavage:

{???} Perfect

Color:

Yellow green, White, Light yellow.

Density:

1.48 - 1.53, Average = 1.5

Habit:

Fibrous - Crystals made up of fibers.

Habit:

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

Hardness:

1-1.5 - Talc or a little harder

Streak:

white

Optical Properties of Motukoreaite

Gladstone-Dale:

CI meas= -0.377 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.264 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.311,KPDmeas= 0.3389,KC= 0.2461
Ncalc = 1.36 - 1.4

Optical Data:

Uniaxial (?), a=1.51, b=1.51, bire=0.0000.

Calculated Properties of Motukoreaite

Electron Density:

Bulk Density (Electron Density)=1.69 gm/cc
note: Specific Gravity of Motukoreaite =1.64 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Motukoreaite= 1.05 barns/electron
U=PE_Motukoreaite x rElectron Density= 1.77 barns/cc.

Radioactivity:

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

Motukoreaite Classification

Dana Class:

17.01.07.01 (17)Compound Carbonates

(17.01)with miscellaneous formulae

(17.01.07)Dana Group

17.01.07.01 Motukoreaite Na2Mg38Al24(CO3)13(SO4)8(OH)108•56(H2O) R 3m 3 2/m

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 Motukoreaite 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 Motukoreaite :
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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Motukoreaite

Na2Mg38Al24(CO3)13(SO4)8(OH)108•56(H2O)
Dana No: 17.01.07.01 Strunz No: 07.DD.35
Locality:

Notes:

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