Scandian ixiolite from Mozambique and Madagascar

Rounded nodules of ixiolite, exceptionally rich in scandium, are found in some granite pegmatites of Zambezia (Mozambique) and Madagascar. The ixiolite from three localities was chemically analyzed. X-ray data are given. It is a well-known fact that pegmatitic scandium will be enriched preferably in the niobiumtantalum minerals of a pegmatite body. Specific scandium minerals such as thortveitite (befanamite) are exceedingly rare. Probably the highest scandium content in a mineral identified as columbite by single crystal X-ray methods was that reported by Haapala et. al. (1967). This columbite which contains 0.90 % Sc203 comes from the Haapaluoma pegmatite in Finland and exhibits a very disordered structural state. More scandium-rich niobium-tantalum minerals are known from the pegmatites of the district of Zambezia, Mozambique, and from those of north and central Madagascar. An unusual 'columbite-tantalite' with 6.00 % Sc 20 3 was reported by v. Knorring (1965) from the Muiane pegmatite mine in Zambezia. The mineral shows an X-ray powder pattern not significantly different from that of a normal columbite-tantalite. In a 'columbite' from the pegmatites of north Madagascar a content of 6.1 % Sc 20 3 was found by Phan et. al. (1967). This mineral also showed an X-ray pattern similar to that of columbite. No single crystal X-ray work was done on either of the two minerals. Both the Mozambique and Madagascar minerals contain appreciable amounts of tin and titanium. On a visit to the Muiane mine in 1966 the second author was able to collect more material of the scandium-rich Zambezia mineral from the dumps of the Mine's sorting factory. The mineral, said to come from the Naquissupa pegmatite in the neighborhood, looked similar to that studied by v. Knorring (op. cit.). During a visit to Madagascar in 1967, the first two authors were given a number of small pieces of the scandium-rich Madagascar mineral from the pegmatites of the Antsirabe area and Betanimena respectively. Because the high scandium contents reported for these niobium-tantalum minerals are unique, the materials collected were subjected to labora76 Oleg v. Knorring, T h. G. Sahama and Martti Lehtinen