MINERAL PROCESSING METHOD OF THE WEEK - OPTICAL SEPARATION!!
This process is used for the concentration of particles that have sufficiently different colours (the best contrast being black and white) to be detected by the naked eye. In addition, electro-optic detectors collect data on the responses of minerals when exposed to infrared, visible, and ultraviolet light. The same principle, only using gamma radiation, is called radiometric separation - Encyclopaedia Britannica.