Gem Instrument Gem Tool Refractometer Diamond Detector External with Light Source Measurement range 1.30-1.81RI I88                Description:         Features:      1.    All kinds of gems can be determined according to the index of refractive index, because different gemstones have fixed refractive index.      2.    This parameter can be used to determine whether a gem is a uniaxial crystal or a biaxial crystal.      3.Unique design, extremely low power consumption and easy to carry.      4.High quality and high accuracy measurement results.      5.Through strict quality and safety standard test, long-term service life.                Product specifications:      1.Measurement range: 1.30 ~ 1.81RI.      2.Minimum dividing value: 0.01RI.      3.Size: about 30x70x130mm.                       Package Includes:       Style A:  1 x Refractometer  1 x Flashlight  Style B:  1 x Refractometer  1 x Refracting oil