Synthetic amethyst grown from hydrothermal method and subsequently irradiated with gamma ray was investigated by polarizing microscopy, emission spectroscopy, atomic absorption spectroscopy, X-ray diffraction electron microscopy, infrared absorption spectroscopy, heating and freezing microscopy, density balance, and optical refractometry. Natural amethysts collected from Sokrisan, Eonyang, and Brazil were also studied to compare their mineralogical and gemmological properties with those of the synthetic counterpart. Synthetic and natural amethysts show exactly or nearly identical properties in specific gravity, refractive index, crystal structure, and chemical composition. In contrast, UV-visible spectrometry and I. R. spectrometry data, solid and fluid inclusion features, and color distribution differ considerably which may be used in differentiating the synthetic from its natural equivalents.