The Amnay ophiolitic complex (AOC), disposed as a northwest-southeast trending ophiolitic unit in Western Mindoro, is made up predominantly of harzburgites with pods/ lenses of lherzolite, websterite, dunite with chromitite, massive gabbro and a mafic volcanic complex.

Complementing geologic, petrologic and structural studies, the geochemistry of the different rocks of an ophiolite suite has become a useful tool in determining the tectonic setting and mineralization potential of a particular exposed upper mantle - crust sequence.

The mafic volcanic rocks of the AOC exhibit calc - alkaline, sub-alkaline to minor tholeiitic characteristics. Furthermore, trends defined in variation diagrams suggest that the source material of the volcanic rocks have undergone relatively low degrees of partial melting. Tectonic discrimination diagrams and spinel chemistries show a predominant mid-ocean ridge with minor island arc geochemical character. This makes the AOC a supra-subduction zone type ophiolite that was formed in a marginal basin environment.

The dominant mid-ocean ridge signature would make the AOC a poor target for significant quantities of ophiolite-related mineralizations. However, the consistent island arc signature together with field observations indicate the possibility of the AOC to host significant metallic deposits, similar to the refractory chromite deposits of the Coto Block of the Zambales ophiolite complex, cannot be discounted.