Precise magnetometers and gravimeters have been used in the Philippines to locate chromite orebodies. Quantitative interpretations of gravimetric data over ultrabasic rocks and magnetic surveys delineate rocks with which chromite may be associated.

Contrasts in densities and magnetic properties are the basis for the applicability of these geophysical methods. For the refractory chromite deposits in Coto, Zambales, the gravity method proved more effective.