OED: A black, magnetic, isometric oxide of nickel and ferric iron, NiFe2O4, belonging to the spinel group. 1921A. F. CROSSE in Jrnl. Chem., Metallurgical & Mining Soc. S. Afr. XXI. 126/2 One of the most interesting mineralogical discoveries..in the Transvaal..is an extraordinarily rich nickel ore… This ore is as far as I am able to…