In this paper, a series of color shades of Taiwan original nephrite stones were studied in the aspect of chemical composition and structural changes of minerals so as to explore the color-causing mechanism. Taiwan nephrite is dominated by tremolite with a small amount of chlorite, and assumes significant felt-like fibers-interwoven metacryst structure. Mineral composition analysis shows that, with the change of the sample color from blue and white through blue-green, green to dark green, the MgO percentage of tremolite varies in order of medium→low→high, and FeO percentage content of tremolite varies in order of low→high→medium. In addition, the content of Cr₂O₃ shows a decreasing trend. Raman spectra show that, with the darkening of color samples, low frequency Raman bands position drifts to lower wavenumber (Fe²⁺ substitution for Mg²⁺ is enhanced).