Ulvospinel
Ulvospinel
a mineral of the subclass of multiple oxides, Fe2Ti04. Ulvospinel crystallizes in the isometric system, and its structure is the inverted form of the spinel structure. It forms solid solutions with magnetite. Lattice disintegration structures form upon cooling. Ulvospinel is found in the form of irregularly shaped black grains and phenocrysts. The unit cell parameter a0(8.40-8.53 Á), the Curie point (from 580° to - 150°C), and the density (5,200-4,800 kg/m3) vary in a regular manner in the magnetite-ulvospinel series. Upon oxidation, ulvospinel alters to ilmenite. It is found in ultrabasic magmatic rocks and lunar basalts. Ulvospinel is a component of complex titanium-magnetite ores.