Pseudobrookite Mineral Data

General Pseudobrookite Information

Chemical Formula:

(Fe+++,Fe++)2(Ti,Fe++)O5

Composition:

Molecular Weight = 238.41 gm

Magnesium 1.02 % Mg 1.69 % MgO

Titanium 15.06 % Ti 25.13 % TiO₂

Iron 50.36 % Fe 19.59 % FeO / 50.24 % Fe₂O₃

Oxygen 33.55 % O

______ ______

100.00 % 96.64 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺_1.5Fe²⁺_0.4Mg_0.1Ti_0.75Fe²⁺_0.25O₅

Environment:

Magmatic, post-volcanic or young volcanic rocks.

IMA Status:

Valid Species (Pre-IMA) 1878

Locality:

Vesuvius and Etna, Italy. Link to MinDat.org Location Data.

Name Origin:

From the Greek pseudo - "I mislead" and the mineral brookite.

Name Pronunciation:

Pseudobrookite + Pronunciation

Synonym:

ICSD 69038

PDF 41-1432

Pseudobrookite Image

Images:

Pseudobrookite

Comments: Black, prismatic crystals of pseudobrookite on matrix.
Location: Sierra County, New Mexico, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Pseudobrookite Crystallography

Axial Ratios:

a:b:c =0.9859:1:0.3751

Cell Dimensions:

a = 9.79, b = 9.93, c = 3.725, Z = 4; V = 362.12 Den(Calc)= 4.37

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Bbmm

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

By Intensity(I/I_o): 3.483(1), 2.748(0.8), 4.902(0.45),

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Forms: ( 1 2 1) ( 0 1 0) ( 1 1 1) ( 2 1 0) ( 1 0 1) ( 1 1 0) ( 1 0 0) ( 1 2 0) ( 1 3 1)

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Physical Properties of Pseudobrookite

Cleavage:

{010} Poor

Color:

Brownish black, Reddish brown, Black.

Density:

4.4

Diaphaneity:

Opaque

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Hardness:

6 - Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Adamantine - Metallic

Streak:

brown

Optical Properties of Pseudobrookite

Gladstone-Dale:

CI meas= -0.055 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.062 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.3158,KPDmeas= 0.3136,KC= 0.2972
Ncalc = 2.3 - 2.31

Optical Data:

Biaxial (+), a=2.35-2.38, b=2.36-2.39, g=2.38-2.42, bire=0.0300-0.0400, 2V(Calc)=62-72, 2V(Meas)=50.

Pleochroism (x):

yellowish brown.

Pleochroism (y):

brown.

Pleochroism (z):

reddish brown.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Pseudobrookite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	22.80	24.00
420 nm	21.90	23.10
440 nm	21.30	22.30
460 nm	20.50	21.40
480 nm	19.80	20.70
500 nm	19.40	20.40
520 nm	19.00	19.90
540 nm	18.50	19.30
560 nm	18.10	18.80
580 nm	17.80	18.50
600 nm	17.50	18.10
620 nm	17.30	17.90
640 nm	17.10	17.70
660 nm	17.00	17.60
680 nm	16.80	17.40
700 nm	16.70	17.30

**Calculated Relative Intensity Colors of Pseudobrookite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	450%	490%
R₁
R₂

Calculated Properties of Pseudobrookite

Electron Density:

Bulk Density (Electron Density)=4.19 gm/cc
note: Specific Gravity of Pseudobrookite =4.40 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_{Pseudobrookite}= 17.92 barns/electron
U=PE_{Pseudobrookite} x rElectron Density= 75.14 barns/cc.

Radioactivity:

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

Pseudobrookite Classification

Dana Class:

07.07.01.01 (07)Multiple Oxides

(07.07)with miscellaneous formulae

(07.07.01)Dana Group

07.07.01.01 Pseudobrookite (Fe,Fe)2(Ti,Fe)O5 Bbmm 2/m 2/m 2/m

07.07.01.02 Armalcolite (Mg,Fe)Ti2O5 Bbmm 2/m 2/m 2/m

07.07.01.03 IMA2000-016! (Ti,Fe,Mg,Mn)1-xTi2O5 Pban 2/m 2/m 2/m

Strunz Class:

04.CB.15 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.C - Metal:Oxygen = 2:3, 3:5, and Similar

04.CB -With medium-sized cations

04.CB.15 Armalcolite (Mg,Fe)Ti2O5 Bbmm 2/m 2/m 2/m

04.CB.15 Mongshanite* (Mg,Cr,Fe)2(Ti,Zr)5O12 Unk Hex

04.CB.15 Pseudobrookite (Fe,Fe)2(Ti,Fe)O5 Bbmm 2/m 2/m 2/m

Other Pseudobrookite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Pseudobrookite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - HyperPhysics
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - University of Colorado - Mineral Structure Data
18 - WWW-MINCRYST

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

Pseudobrookite

(Fe+++,Fe++)2(Ti,Fe++)O5
Dana No: 07.07.01.01 Strunz No: 04.CB.15
Locality:

Notes:

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