| |
 |
Allophane Mineral Data
|
|
|
General Allophane Information
|
 Chemical Formula: |
Al2O3•(SiO2)1.3-2•((H2O))2.5-3 |
| 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 |
| Empirical Formula: |
(Al2O3)(SiO2)1.3•2.5(H2O) |
| Environment: |
In marlstone rocks (TL) and weathering product of volcanic ash. |
| IMA Status: |
Valid Species (Pre-IMA) 1816 |
| Locality: |
Grafenthal, Thuringia, Germany Link to MinDat.org Location Data. |
| Name Origin: |
From the Greek allos - "other" and phanos - "to appear" in allusion to its change when blowpiped. |
| Name Pronunciation: |
Allophane + Pronunciation  |
| Synonym: |
Ilbaite |
| |
Protoallophane |
| |
Schrotterite |
| |
Allophane Image |
|
Images:
|
|
Allophane
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
|
| Crystal System: |
Amorphous- No Crystals |
| 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
|
| Cleavage: |
None |
| Color: |
White, Green, Blue, Yellow, Brown. |
| Density: |
1.9 |
| Diaphaneity: |
Translucent |
| Fracture: |
Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). |
| Habit: |
Botryoidal - "Grape-like" rounded forms (e.g.. malachite). |
| Habit: |
Encrustations - Forms crust-like aggregates on matrix. |
| Habit: |
Stalactitic - Shaped like pendant columns as stalactites or stalagmites (e.g. calcite). |
| Hardness: |
3 - Calcite |
| Luminescence: |
Fluorescent, Short UV=blue. |
| Luster: |
Waxy |
| Streak: |
white |
| |
Optical Properties of Allophane
|
| Gladstone-Dale: |
CI meas= -0.087 (Poor) - where the CI = (1-KPDmeas/KC)
KPDmeas= 0.2542,KC= 0.234
Ncalc = 1.44 |
| Optical Data: |
Isotropic, n=1.47-1.496. |
| |
Calculated Properties of Allophane
|
| Electron Density: |
Bulk Density (Electron Density)=1.92 gm/cc
note: Specific Gravity of Allophane =1.90 gm/cc.
|
| Fermion Index: |
Fermion Index = 0.0078541141
Boson Index = 0.9921458859 |
| Photoelectric: |
PEAllophane = 1.37 barns/electron
U=PEAllophane x rElectron Density= 2.64 barns/cc.
|
| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Allophane is Not Radioactive |
| |
Allophane Classification
|
| Dana Class: |
71.01.04.01 (71)Phyllosilicate Sheets of Six-Membered Rings |
| |
(71.01)with 1:1 layers |
| |
(71.01.04)Allophane group |
| |
71.01.04.01 Allophane Al2O3•(SiO2)1.3-2•((H2O))2.5-3 None |
| |
71.01.04.02 Hisingerite Fe2Si2O5(OH)4•2(H2O) Unk Mono |
| |
71.01.04.03 Imogolite Al2SiO3(OH)4 ? Mono |
| |
71.01.04.04 Neotocite (Mn,Fe)SiO3•(H2O)(?) None |
| |
71.01.04.05 Zinalsite! Zn2AlSi2O5(OH)4•2(H2O)(?) Mono |
| 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
|
| References: |
NAME( Dana8) PHYS. PROP.(Collectors Book of Fluorescent Minerals) OPTIC PROP.(Heinrich65) |
| 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
Search for Allophane using:
[AOL]
[Bing]
[Dog Pile]
[GeoScienceWorld]
[HotBot]
[Ixquick]
[Lycos]
[MAMMA]
[Scirus]
[Teoma]
[WebCrawler]
[Wikipedia]
[YAHOO]
Visit our Advertisers for Allophane :
Ask about Allophane here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espaņol
Print or Cut-and-Paste your Allophane Specimen Label here :
|
Allophane
Al2O3•(SiO2)1.3-2•((H2O))2.5-3
Dana No: 71.01.04.01 Strunz No: 09.ED.20
Locality:
Notes:
|
|
| |
| |
|
| |
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.