A handheld Penta prism spectroscope for visible light shows the absorption lines of the elements involved in producing its color. Spectroscope breaks up the light that is being transmitted from a gemstone to its spectral colors. Making this one of the most important tools in identifying gemstones. They help distinguish naturally colored diamonds from those that have been irradiated and help to distinguish natural stones from synthetics by the stone s selective absorption of certain wavelengths. A Penta Prism spectroscope has 5 prism structure inside which allows a gemologist to see the different wavelengths absorbed by a particular stone. It is a more accurate spectroscope than the diffraction grating spectroscope and quite handy too.