Pseudomorphs of Goethite after Pyrite from Yamasa Village, Shimane Prefecture

Very common pseudomorphs of so-called limonite after pyrite may be presumed in most instance to be goethite, but true identification of goethite has not been shown in Japan. In this report, a mineralogical study of limonite pseudomorphs after pyrite from Yamasa Village in given. Limonite pseudomorphs of about 0.5 to 2 cm in size show hexahedral forms, the surface of the crystal oxidized to limonite, and relict pyrite in its interior penetrated by veinlets of limonite, as the microscopic examination of polished section shows. Investigations by X-ray and other methods show that limonite after pyrite from Yamasa village consists, for the most part, of goethite