Jedwabite

General Information: Chemical Formula:Fe7(Ta,Nb)3 Composition:(Molecular Weight = 708.80 gm)Tantalum 38.29 % TaNiobium 6.55 % NbIron 55.15 % Fe Empirical Formula: Fe0+7Ta1.5Nb0.5 Environment:Discovered in platiniferous placers in the Nizhnetagilsky District in the Middle Urals, in a collection made by P. Walther at the beginning of the 20th century, in association with niobocarbide and a tantalum carbide. IMA Status:Approved IMA 1995 Locality:Nijniy-Tagil, near Solovjeva mountains (formerly Aurorinsky mine) and Baranchinsky massif near the Aktai River, Middle Urals, Russia. Name Origin:For Jacques Jedwab, Universit‚ Libre de Bruxelles, Belgique, in recognition of his meticulous investigations of the mineralogy of placers and of carbides in natural environments.Physical Properties: Cleavage:None Color:grayish yellow. Density:8.6 Diaphaniety:Opaque Habits:Granular - Generally occurs as anhedral to subhedral crystals in matrix., , Hardness:7 - Quartz Luster:MetallicMore details...