JOSEPHINITE: A UNIQUE NICKEL-IRON.

Abstract

Josephinite, terrestrial native nickel-iron from Josephine County, southwest Oregon, is uniquely different from nickel-iron metal (awaruite) found in any other of its numerous serpentinite occurrence worldwide. Josephinite is actually a rock containing two or more native metal phases intergrown with silicate minerals. This paper describes specimens that contain fine crystallographically oriented intergrowths of nickel-rich taenite ( gamma -Fe,Ni) and awaruite (FeNi//3) with andradite garnet. This mineral association has not been reported from any other locality. Metallographic, mineralogical, and chemical analyses performed indicate that josephinite probably formed over a range of temperatures in a chemically evolving serpentinization environment. This extensive study differentiates between two contrasting metallogenic regimes of serpentinization. Refs.