Abstract: An optical method for identifying an immobile target having a homogeneous surface is disclosed. Light reflected from the surface of the target is electro-optically detected. The Stokes parameters of the detected light are measured in four preselected, adjacent, spectral bands. A discrete value termed the polarization intensity index (PII) is calculated using the measured Stokes parameters. Each homogeneous surface has a characteristic PII value. Substantially identical surfaces display substantially identical PII values. By comparing PII values of unidentified target surfaces with a set of previously determined PII values for different, known target surfaces, the geological nature of an unidentified target surface may be determined.