In accordance with the invention, the quality of hard gold is determined by Raman vibrational spectroscopy. A sample of the hard gold is provided, a monochromatic light beam is directed onto the sample, and the frequency and intensity of the light scattered by the sample is analyzed for the vibrational frequencies of polymer molecules. Scattering frequencies offset from the initial beam frequency by about 2132 cm−1 and about 2182 cm−1, for example, are indicative of high quality nickel-hardened gold.