Allophane
Propiedades fisicas
Hábito: Stalactitic, encrustations or botryoidal
Lustre: Ceroso
Transparencia: Translúcido
Color: Yellow, white, green, brown or blue
Raya: Blanco
Dureza (Mohs): 2-3
Tenacidad: Frágil
Fractura: Concoidal
Densidad: 1,9 g/cm3 (medida)
Cristalografía
Sistema cristalino:Amorfo
Clase (H-M): 0m () - Indefinida
Difracción de Rayos X:| D(hkl) | Intensidad |
|---|---|
| 11 | 100 |
| 3,3 | 80 |
| 2,2 | 60 |
Propiedades ópticas
Tipo: Isotrópico
Valores RI: nα= 1,47 - 1,496
Dispersión: Ninguna
Propiedades químicas
Fórmula: (Al2O3)(SiO2)1.3-2·2.5-3H2O
Elementos químicos: Al, O, Si, H
Composición química: Si: 16,22%, H: 2,24%, Al: 23,97%, O: 57,57%, H2O: 7,99%,
Tests químicos
Fusibilidad: 7; Mineral tipo: Cuarzo; Punto de fusión: 1710ºC; Infusible con soplete
Reacción a los ácidos: Decomposes in hydrochloric acid with the separation of gelatinous silica.
Ensayos en tubo cerrado: Gives off water.
Formación de sublimados: With cobalt nitrate gives a blue mass indicating aluminium.
Otras propiedades
Luminiscente: Yellow-white, white, orange or green
Magnetismo: No magnético
Relaciones con otros minerales
Minerales acompañantes
| Imagen | Mineral | Fórmula | Sistema | Dureza | Color | Raya | Brillo |
|---|---|---|---|---|---|---|---|
 | Halloysita | Al2(Si2O5)(OH)4 | Triclínico | 1-2 | Blanco | Terroso | |
 | Limonita | FeO(OH)·nH2O | Amorfo | 5-5,5 | Pardo | Pardo amarillenta | Adamantino - sedoso |
Yacimientos y localidades de interés
Localidades
- Gräfenthal, Saalfeld (near), Thüringen, Germany - Localidad tipo.
- Greifenstein, Ehrenfriedersdorf, Sachsen, Germany - Localidad tipo.
- Schwaz-Brixlegg, Tyrol, Austria
- El Dragón mine, Quijarro, Potosí Dept, Bolivia
- Siglo Veinte (XX) mine, Llallagua, Bustillo, Potosí Dept, Bolivia
- Borovec, Zdar nad Sazavou, Maehren, Czech Republic
- Brandelhow Mine, Brandlehow, Cumbria, England
- Bridestowe, Devon, England
- Carrock mine, Caldbeck Fells, Cumbria, England
- Clifton Hill, Sussex, England
- Driggith Mine, Caldbeck Fells, Cumbria, England
- East Harptree dumps, Bristol, Somerset, England
- Garras mine, St. Erme, Cornwall, England
- Hampstead Farm quarry, Chipping Sodbury, Gloucestershire, England
- Hawkswood mine, North Hill, Cornwall, England
- Hazard Section, Botallack mine, Botallack, St. Just, Cornwall, England
- Irchester, Northamptonshire, England
- Old Potts Gill mine, Caldbeck Fells, Cumbria, England
- Port Quin, St. Endellion, Cornwall, England
- Purley Downs, Surrey, England
- Wheal Hazard, St. Just, Cornwall, England
- Wheal Phoenix, Linkinhorne, Cornwall, England
- Woodleaze Quarry, Tytherington Quarries, Gloucestershire, England
- Cap Garonne, Le Pradet, Var, France
- Chessy-les-Mines, Rhône, Rhône-Alpes, France
- Clara mine, Oberwolfach, Baden-Wuerttemberg, Germany
- Daniel mine, Schneeberg, Sachsen, Germany
- Glücksrad mine, Clausthal-Zellerfeld, Harz Mts, Sachsen, Germany
- Gräfenthal, Saalfeld, Thüringen, Germany
- Hühn mine, Trusetal, Bad Salzungen, Thüringen, Germany
- Johann mine, Wittichen, Baden-Wuerttemberg, Germany
- Königswart, Freudenstadt, Baden-Wuerttemberg, Germany
- Rammelsberg mine, Goslar, Harz Mts, Sachsen, Germany
- Silberbrünnle mine, Kinzigtal, Baden-Wuerttemberg, Germany
- Hilarion adit, Agios Konstandinos, Laurion, Attica, Greece
- Cassagna and Monte Bianco Mines, Val Graveglia, Liguria, Italy
- Gambatesa mine, Reppia, Val Graveglia, Liguria, Italy
- Molinello mine, Val Graveglia, Liguria, Italy
- Monte Copello-Reppia Prospect, Val Graveglia, Liguria, Italy
- Val Graveglia, Liguria, Italy
- Chaidarkan, Alai, Kyrgyzstan
- Chauvay, Alai, Kyrgyzstan
- Khaidarkan deposit, Kyrgyzstan
- Boleo, Santa Rosalia, Baja California, Mexico
- Trearne Quarry, Beith, Ayrshire, Scotland
- Pezinok Mine, Malé Karpaty Mts, Slovakia
- Bisbee, Cochise Co., Arizona, USA
- Bristol Copper Mine, Bristol, Hartford Co., Connecticut, USA
- Butte General Area, Montana, USA
- Callahan mine, Brooksville, Hancock Co., Maine, USA
- Copper Queen Mine, Bisbee, Cochise Co., Arizona, USA
- Galena/Baxter Springs/Lawton, Cherokee Co., Kansas, USA
- General Area, Jasper & Newton counties, Missouri, USA
- General Area, Picher/Commerce/Quapaw/Miami/Peoria, Ottowa Co., Oklahoma, USA
- Goldberg, Custer Co., Idaho, USA
- Graphic mine, Magdalena District, Socorro Co., New Mexico, USA
- Magdalena district, Socorro Co., New Mexico, USA
- Magnet Cove, Hot Spring Co., Arkansas, USA
- New Cornelia Mine, Ajo, Pima Co., Arizona, USA
- Trap rock Quarry, Chesire, New Haven Co., Connecticut, USA
- New Pandora mine, Llanwrst, Gwynedd, Wales
Bibliografía y más información
- American Mineralogist, vol. 61, p.379, (1976)