The differentiation of natural and synthetic gems is still a difficult problem in gems identification. The full width at half maximum (FWHM) of Raman spectrum, that is the life-span of phonon, can provide valuable information about. natural or synthetic gem. Analysis of the natural and synthetic ruby was performed by BTR111--785 mini-Raman spectroscopy, and it was found that the FWHM of natural ruby is more than 10 cm(-1), withal the FWHM of synthetic ruby is less than 10 cm(-1).