Goethite
| Formula | alpha-Fe3+O(OH) |
| Origin | Mina Filon Sur, Alosno (Spanien) |
| Description | rod-shaped brown partly iridescent goethite |
| Classification (Lapis) | Hydroxides |
| Crystal System | monoclinic |
| Hardness | 5,0 – 5,5 |
| Colour | blackish brown; yellowish to reddish brown in massive aggregates, may be banded |
| Streak | brownish |
| Luminescence | none observed |
| Luster | metallic |
| Transparency (Opacity) | opaque |
| Cleavage | perfect |
| Fracture | uneven |
| Magnetism | negative |
| Geological Setting | a common weathering product derived from numerous iron-bearing minerals in oxygenated environments |
| Specific Gravity | 4,28 g/cm3 |
Kristallmodell
#© Mark Holtkamp
