Brookite Mineral Data
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 - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pcab
X Ray Diffraction:
By Intensity(I/Io ): 3.51(1), 2.9(0.9), 3.47(0.8),
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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/electronU=PEBrookite x r Electron 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)
See Also:
Links to other databases for Brookite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - EUROmin Project
7 - Ecole des Mines de Paris
8 - Franklin Minerals(Dunn)
9 - GeoScienceWorld
10 - Google Images
11 - Google Scholar
12 - Handbook of Mineralogy (MinSocAm)
13 - Handbook of Mineralogy (UofA)
14 - HyperPhysics
15 - MinDAT
16 - Mineralienatlas (Deutsch)
17 - Online Mineral Museum
18 - Philatelic Mineralogy
19 - QUT Mineral Atlas
20 - Ruff.Info
21 - Scandinavian mineral gallery
22 - University of Colorado - Mineral Structure Data
23 - WWW-MINCRYST
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Brookite
TiO2
Dana No: 04.04.05.01 Strunz No: 04.DD.10
Locality:
Notes:
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