Macaulayite Mineral Data

General Macaulayite Information

Chemical Formula:

(Fe+++,Al)24Si4O43(OH)2

Composition:

Molecular Weight = 2,116.93 gm

Aluminum 2.55 % Al 4.82 % Al₂O₃

Iron 58.04 % Fe 82.98 % Fe₂O₃

Silicon 5.31 % Si 11.35 % SiO₂

Hydrogen 0.10 % H 0.85 % H₂O

Oxygen 34.01 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₂₂Al₂Si₄O₄₃(OH)₂

Environment:

Deeply weathered granite.

IMA Status:

Approved IMA 1984

Locality:

Bennachie car park, 7 km NW of Inverurie, Aberdeenshire, Scotland. Link to MinDat.org Location Data.

Name Origin:

Named for the Macaulay Institute for Soil Research.

Name Pronunciation:

Macaulayite + Pronunciation

Macaulayite Crystallography

Axial Ratios:

a:b:c =0.5773:1:4.1647

Cell Dimensions:

a = 5.038, b = 8.726, c = 36.342, Z = 2; beta = 92° V = 1,596.68 Den(Calc)= 4.40

Crystal System:

Monoclinic Space Group: C?

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

By Intensity(I/I_o): 2.533(1), 1.462(0.35), 2.72(0.35),

Physical Properties of Macaulayite

Cleavage:

{001} Good

Color:

Blood red.

Density:

4.41

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Luster:

Earthy (Dull)

Streak:

light red

Optical Properties of Macaulayite

Gladstone-Dale:

CI meas= 0.441 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.44 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1668,KPDmeas= 0.1664,KC= 0.2979
Ncalc = 2.31

Optical Data:

Biaxial (?), a=1.734

Pleochroism (x):

pale red.

Pleochroism (z):

yellow.

Calculated Properties of Macaulayite

Electron Density:

Bulk Density (Electron Density)=4.22 gm/cc
note: Specific Gravity of Macaulayite =4.40 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Macaulayite= 17.88 barns/electron
U=PE_Macaulayite x rElectron Density= 75.51 barns/cc.

Radioactivity:

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

Macaulayite Classification

Dana Class:

71.02.05.01 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.02)with 2:1 Layers

(71.02.05)Dana Group

71.02.05.01 Macaulayite (Fe,Al)24Si4O43(OH)2 C? Mono

Strunz Class:

09.EC.65 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.65 Macaulayite (Fe,Al)24Si4O43(OH)2 C? Mono

Other Macaulayite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Macaulayite :
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 Macaulayite Specimen Label here :

Macaulayite

(Fe+++,Al)24Si4O43(OH)2
Dana No: 71.02.05.01 Strunz No: 09.EC.65
Locality:

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