Mineralogy Database

Boehmite Mineral Data

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General Boehmite Information

Help on Chemical  Formula: Chemical Formula: AlO(OH)
Help on Composition: Composition: Molecular Weight = 59.99 gm
   Aluminum  44.98 %  Al   84.98 % Al2O3
   Hydrogen   1.68 %  H    15.02 % H2O
   Oxygen    53.34 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: AlO(OH)
Help on Environment: Environment: Major constituent of most bauxite ores.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1927
Help on Locality: Locality: Subtropical areas (Jamaica, Surinam, Guyana, Georgia, USA. France, Hungary, Russia, Greece, Australia, and Guinea) of high rainfall where lateritic soils can develop on Al-bearing igne Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the German geologist and paleontologist, J. Bohm (1857-1938).
Help on Name Pronunciation: Name Pronunciation: Boehmite Say BOEHMITE
Help on Synonym: Synonym: Bauxite - Al ore mixture
  Cliachite - colloidal Al hydroxide
  Kliachite - colloidal Al hydroxide
  Pseudoboehmite - colloidal b�hmite

Boehmite Image

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Comments: Crystalline boehmite in bauxite rock.
Location: Bauxite, Saline County, Arkansas, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Boehmite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.2345:1:0.3026
Help on Cell Dimensions: Cell Dimensions: a = 2.868, b = 12.227, c = 3.7, Z = 4; V = 129.75 Den(Calc)= 3.07
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Amam
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 6.11(1), 3.164(0.65), 2.346(0.53),

Physical Properties of Boehmite

Help on Cleavage: Cleavage: {010} Good
Help on Color: Color: White, Light yellow, Yellowish green.
Help on Density: Density: 3 - 3.07, Average = 3.03
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Habit: Habit: Pistolitic - > 3mm rounded spherical grains.
Help on Hardness: Hardness: 3 - Calcite
Help on Luster: Luster: Vitreous - Pearly
Help on Streak: Streak: white

Optical Properties of Boehmite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.052 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.063 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2127,KPDmeas= 0.2152,KC= 0.227
Ncalc = 1.68 - 1.7
Help on Optical Data: Optical Data: Biaxial (+), a=1.646, b=1.652, g=1.661, bire=0.0150, 2V(Calc)=80, 2V(Meas)=80.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
Help on Pleochroism (z): Pleochroism (z): colorless.

Calculated Properties of Boehmite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.04 gm/cc
note: Specific Gravity of Boehmite =3.04 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0002585608
Boson Index = 0.9997414392
Help on Photoelectric: Photoelectric: PEBoehmite = 1.35 barns/electron
U=PEBoehmite x rElectron Density= 4.09 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Boehmite is Not Radioactive

Boehmite Classification

Help on  Dana Class: Dana Class: (06)Hydroxides and Oxides Containing Hydroxyl
  (06.01)where X+++O OH
  (06.01.02)Boehmite Group Boehmite AlO(OH) Amam 2/m 2/m 2/m Lepidocrocite FeO(OH) Amam 2/m 2/m 2/m Guyanaite CrO(OH) Pnnm 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 04.FE.15 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.F - Hydroxides (without V or U)
  04.FE -Hydroxides with OH, without H2O; sheets of edge-sharing octahedra
04.FE.15 Boehmite AlO(OH) Amam 2/m 2/m 2/m
04.FE.15 Lepidocrocite FeO(OH) Amam 2/m 2/m 2/m

Other Boehmite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Boehmite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - University of Colorado - Mineral Structure Data

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Dana No: Strunz No: 04.FE.15





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