A Double Barrel Penta prism spectroscope is unique but essential equipment for a Gemologist. It comes with two barrels, one for the visible spectrum of light and the other shows the scale of the spectrum which is adjustable with a screw at the end. This spectroscope is the same as the one which is mounted on a Spectroscope station. It shows the absorption lines of the elements involved in producing the color in a gemstone. Spectroscope breaks up the light that is being transmitted from a gemstone to its spectral colors. 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. This spectroscope is manufactured by Alfa Mirage Ltd. in Japan and has very good quality.