An instrument used to discriminate Natural Emeralds/ Natural Spinels from imitations and synthetic creations. This is a dichromatic colour filter transmitting light of only two wavelength regions – one in deep red and the other in yellow – green.
An instrument used to discriminate Natural Emeralds/ Natural Spinels from imitations and synthetic creations. This is a dichromatic colour filter transmitting light of only two wavelength regions – one in deep red and the other in yellow – green.