Gemological Gem/Gemstone Refractometer/Tester Refractoscope, Gemmological instrument, Gemology Tool , Gemological instrument Gemological Gem/Gemstone ... Refractometer/TesterRefractoscope, Gemmological instrument,Gemology Tool ,Gemological instrument-----------------------------------------------------------------Gem Tester Refractometer is one of most important optical parameter. Gloss of ...