GOETHITE

Italcementi Quarry, Magrè, Schio, Vicenza Province, Veneto, Italy

Fe3+O(OH)

Crystal System: orthorhombic
Colour: brownish black, yellow-brown or reddish brown
Lustre: adamantine, silky, metallic, dull
Habitus: prismatic or tabular 
Hardness: 5 - 5½
Fracture:  irregular/uneven
Cleavage: perfect {010}; {100} less perfect.
Density: 4.18 g/cm
Origin and geological occurrence: a weathering product derived from numerous iron-bearing rocks in oxydizing environment. Goethite is also a primary precipitate in hydrothermal, marine, and bog environments upon oxidation of reduced iron-bearing waters. 

 

www.mindat.org 
Smorf link

Samples:

4.18 GOETHITE2

4.18 Goethite

Mammilary aggregate of fibrous-radiated crystals of goethite. Rio Marina, Elba Island, Tuscany, Italy.

 #oxides

4e27 goehite

4.27 Goethite
Mammillary aggregate of goethite. 

 #oxides