Lepidocrocite (γ-FeO(OH)), also called esmeraldite or hydrohematite, is an iron oxide-hydroxide
mineral. Lepidocrocite has an orthorhombic crystal structure, a hardness of 5, specific gravityof 4, a submetallic luster and a yellow-brown streak. It is red to reddish brown and forms when iron-containing substances rustunderwater. Lepidocrocite is commonly found in the weatheringof primary iron minerals and in iron oredeposits. It can be seen as rust scale inside old steel water pipes and water tanks.
The structure of lepidocrocite is similar to the
boehmitestructure found in bauxiteand consists of layered iron(III) oxide octahedra bonded by hydrogen bondingvia hydroxidelayers. This relatively weakly bonded layering accounts for the "scaley" habit of the mineral.
It was first described in 1813 from the Zlaté Hory
polymetallic oredeposit in Moravia, Czech Republic. The name is from the Greek "lipis" for "scale" and "krokis" for "fibre."
* [http://webmineral.com/data/Lepidocrocite.shtml Webmineral data]
* [http://www.mindat.org/show.php?id=2379&ld=1&pho= Mindat with locality data]
* [http://www.uwgb.edu/dutchs/PETROLGY/LepidocrStruc.HTM "Lepidocrocite and Boehmite Structure"] , Steven Dutch, 08 March 2002.
Wikimedia Foundation. 2010.