Brookite Mineral Data (original) (raw)

General Brookite Information

Chemical Formula:

TiO2

Composition:

Molecular Weight = 79.88 gm

Titanium 59.94 % Ti 100.00 % TiO2

Oxygen 40.06 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

TiO2

IMA Status:

Valid Species (Pre-IMA) 1825

Locality:

Magnet Cove near Hot Springs, Arkansas, USA. Link to MinDat.org Location Data.

Name Origin:

Named after the English mineralogist, Henry James Brucke (1771-1857), a London mineralogist and wool trader.

Name Pronunciation:

Brookite

Synonym:

ICSD 36408

PDF 29-1360

Brookite Image

Images:

	Brookite Comments: Brookite crystal group on matrix. During the 19th century this site produced some of the best brookite ever seen. Location: Classic Welsh locality of Prenteg, Gwynedd, Wales, UK.Scale: 4 x 4.5 cm. © Fabre Minerals

Brookite Crystallography

Axial Ratios:

a:b:c =0.5942:1:0.5601

Cell Dimensions:

a = 5.456, b = 9.182, c = 5.143, Z = 8; V = 257.65 Den(Calc)= 4.12

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pcab

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

By Intensity(I/Io): 3.51(1), 2.9(0.9), 3.47(0.8),

Forms:

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| | Forms:( 1 1 2) ( 1 1 0) Warning: this large pop-up is very compute intensive and may not work well with some computers. | | -------------------------------------------------------------------------------------------------------------------------------------- |

Crystal Structure:

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| | Meagher E P , Lager G A , The Canadian Mineralogist , 17 (1979) p.77-85, Polyhedral thermal expansion in the TiO2 polymorphs: Refinement, of the crystal structures of rutile and brookite at high temperature, Sample at 25 degrees C View Additional jPOWD Structure files for Brookite [1] [2] [3] [4] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

Physical Properties of Brookite

Cleavage:

{120} Indistinct

Color:

Brown, Light brown, Dark brown, Dark reddish brown, Orange.

Density:

4.1 - 4.14, Average = 4.11

Diaphaneity:

Transparent to translucent to opaque

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Platy - Sheet forms (e.g. micas).

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5.5-6 - Knife Blade-Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Sub Metallic

Streak:

yellowish white

Optical Properties of Brookite

Gladstone-Dale:

CI meas= -0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.3958,KPDmeas= 0.3958,KC= 0.393
Ncalc = 2.61 - 2.63

Optical Data:

Biaxial (+), a=2.583-2.584, b=2.584-2.588, g=2.705-2.741, bire=0.1220-0.1570, 2V(Calc)=12-20, 2V(Meas)=10. Dispersion relatively strong.

Calculated Properties of Brookite

Electron Density:

Bulk Density (Electron Density)=3.92 gm/cc
note: Specific Gravity of Brookite =4.12 gm/cc.

Fermion Index:

Fermion Index = 0.07
Boson Index = 0.93

Photoelectric:

PEBrookite = 10.03 barns/electron
U=PEBrookite x rElectron Density= 39.34 barns/cc.

Radioactivity:

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

Brookite Classification

Dana Class:

04.04.05.01 (04)Simple Oxides

(04.04)with a cation charge of 4+ (A++++ O2)

(04.04.05)Dana Group

04.04.05.01 Brookite TiO2 Pcab 2/m 2/m 2/m

Strunz Class:

04.DD.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DD -With medium-sized cations; frameworks of edge-sharing octahedra

04.DD.10 Brookite TiO2 Pcab 2/m 2/m 2/m

Other Brookite Information

References:

NAME( Lapis) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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

Brookite

TiO2
Dana No: 04.04.05.01 Strunz No: 04.DD.10
Locality:

Notes: