Mineralogy Database

Allophane Mineral Data

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General Allophane Information

Help on Chemical  Formula: Chemical Formula: Al2O3•(SiO2)1.3-2•((H2O))2.5-3
Help on Composition: Composition: Molecular Weight = 225.11 gm
   Aluminum  23.97 %  Al   45.29 % Al2O3
   Silicon   16.22 %  Si   34.70 % SiO2
   Hydrogen   2.24 %  H    20.01 % H2O
   Oxygen    57.57 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: (Al2O3)(SiO2)1.3•2.5(H2O)
Help on Environment: Environment: In marlstone rocks (TL) and weathering product of volcanic ash.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1816
Help on Locality: Locality: Grafenthal, Thuringia, Germany Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek allos - "other" and phanos - "to appear" in allusion to its change when blowpiped.
Help on Name Pronunciation: Name Pronunciation: Allophane + Pronunciation Say ALLOPHANE
Help on Synonym: Synonym: Ilbaite

Allophane Image

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Comments: Blue, cuprian, botryoidal allophane on matrix.
Location: Reiche Zeche Mine, Himmelfahrt Mine, Freiberg, Freiberg District, Erzgebirge, Saxony, Germany. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Allophane Crystallography

Help on Crystal System: Crystal System: Amorphous- No Crystals
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.3(1), 2.25(0.2), 1.4(0.1),1.23(0.05), 1.86(0.05),

Physical Properties of Allophane

Help on Cleavage: Cleavage: None
Help on Color: Color: White, Green, Blue, Yellow, Brown.
Help on Density: Density: 1.9
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Habit: Habit: Botryoidal - "Grape-like" rounded forms (e.g.. malachite).
Help on Habit: Habit: Encrustations - Forms crust-like aggregates on matrix.
Help on Habit: Habit: Stalactitic - Shaped like pendant columns as stalactites or stalagmites (e.g. calcite).
Help on Hardness: Hardness: 3 - Calcite
Help on Luminescence: Luminescence: Fluorescent, Short UV=blue.
Help on Luster: Luster: Waxy
Help on Streak: Streak: white

Optical Properties of Allophane

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.087 (Poor) - where the CI = (1-KPDmeas/KC)
KPDmeas= 0.2542,KC= 0.234
Ncalc = 1.44
Help on Optical Data: Optical Data: Isotropic, n=1.47-1.496.

Calculated Properties of Allophane

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=1.92 gm/cc
note: Specific Gravity of Allophane =1.90 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0078541141
Boson Index = 0.9921458859
Help on Photoelectric: Photoelectric: PEAllophane = 1.37 barns/electron
U=PEAllophane x rElectron Density= 2.64 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Allophane is Not Radioactive

Allophane Classification

Help on  Dana Class: Dana Class: (71)Phyllosilicate Sheets of Six-Membered Rings
  (71.01)with 1:1 layers
  (71.01.04)Allophane group Allophane Al2O3•(SiO2)1.3-2•((H2O))2.5-3 None Hisingerite Fe2Si2O5(OH)4•2(H2O) Unk Mono Imogolite Al2SiO3(OH)4 ? Mono Neotocite (Mn,Fe)SiO3•(H2O)(?) None Zinalsite! Zn2AlSi2O5(OH)4•2(H2O)(?) Mono
Help on  Strunz Class: Strunz Class: 09.ED.20 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.ED -Phyllosilicates with kaolinite layers
09.ED.20 Allophane Al2O3•(SiO2)1.3-2•((H2O))2.5-3 None
09.ED.20 Chrysocolla (Cu,Al)2H2Si2O5(OH)4•n(H2O) Unk Ortho
09.ED.20 Neotocite (Mn,Fe)SiO3•(H2O)(?) None
09.ED.20 Imogolite Al2SiO3(OH)4 ? Mono

Other Allophane Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Collectors Book of Fluorescent Minerals) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Allophane :
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
15 - YupRocks

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Dana No: Strunz No: 09.ED.20





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