Allophane Mineral Data (original) (raw)

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

Protoallophane

Schrotterite

Allophane Image

Click Here for Larger Allophane Image in a New Browser Window Images:

Click Here for Larger Allophane Image 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

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:

71.01.04.01 (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

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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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 Espa�ol

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: