A dichroscope is a handheld tool for identifying or looking into the different colors or shades of a pleochroic piece of gemstones. It helps any gemologist or gem cutter in judging gemstone before cutting or identifying any gem.
Calcite Dichroscope is used to observe dichroic gems and trichroic gems regarding observing two different Colours in gem or three different Colours in gemstones. The gems with having strong difference of colors separately will be called Pleochroic. It works because the calcite rhomb (Iceland spar) separates the polarized slow and fast ray emerging from the gemstone. If you look at the viewing end of the dichroscope, two small windows are seen. A gemstone is placed infront of Iceland spar with having white light in back side. Light enters through Aperture. Calcite rhomb separates the pleochronism clours in the gemstone.
There has been taken in this picture, a close look of emerald through Samsung mobile camera by zooming it. If you see, this emerald is showing two different Colours. One is green and one is yellow green.
I will upload another video showing garnet plane colour.
1—This helps in identification of gemstones.
2—It shows the true Colours of Pleochroic gem along each axis. It helps in cutting.
3—A gem cutter can judge the strongest colour and then he cuts accordingly for the best results.
…. Non crystallized material will have same colour in both two windows.
… Crystallized material will have two different Colours to be viewed in these windows.