Lepidocrocite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Hydroxides and hydrates
Crystal system : Orthorhombic
Chemistry : FeO(OH)
Rarity : Common
Lepidocrocite is a dimorph of goethite to which it closely resembles. It is less common than this and is mainly found in the alteration zone of metallic hydrothermal deposits, it is a minority constituent of laterites. Its name comes from the Greek lepidos (scale) and krokus (fiber, filament), thus emphasizing its often scaly or feathery habit. Lepidocrocite rarely appears in very flattened tabular crystals of {010} small size (2 mm), they are often gathered in rosettes or aggregates. Lepidocrocite occurs more frequently in lamellar, scaly or fibrous masses. It has a strong adamantine to submetallic luster, a dark brownish red to blackish purplish brown color. It is an accessory iron ore.
Main photo : Lepidocrocite of Echassières, Allier, France © Yannick Vessely
Lepidocrocite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 5
Density : 4.05 to 4.13
Fracture : Undeterminated
Streak : Orange
TP : Translucent to transparent
RI : 1.940 to 2.510
Birefringence : 0.570
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : None