Paragenesis of Oxide Minerals in Some Emery Ores

Abstract

Emery ore can be classified into two types; corundum-spinel emery and spinel-free corundum emery. In this study paragenetic relationships of Fe-Ti oxides and Fe-Al oxides in emery ores from the Shin-Kiura mine, Matsubase, Peekskill and Naxos are described and are explained in terms of oxidation-reduction conditions during the formation of the ore.
In corundum-spinel emery the most abundant Fe-Ti oxide mineral is ilmenite while smaller amount of magnetite is some-times also present. In spinel-free corundum emery, on the other hand, titanohematite is invariably present either as hemo-ilmenite or ilmeno-hematite. Martitized magnetite is also present in spinel-free ores from the Shin-Kiura mine and Naxos.
Such paragenetic relationships indicate that spinel-free emery was formed under more oxidizing conditions compared with spinel bearing emery.