1.30-1.81RI Rang Gemstone Refractometer Built-in Gem Tester

Refractive Index is one of the most important optical parameters used to identify and authenticate polished precious and semi-precious gemstones. This Gemological refractometer is a low cost, lightweight measuring instrument used by jewellers and traders of gemstones to measure polished stones over a refractive index range of 1.30 to 1.81 RI. The instrument can also be used to identify whether a particular stone is Isotropic or Anistropic (uniaxial or biaxial). Features: 1. Can identify singly & doubly gemstones quickly and accurately. 2. Uniquely designed, low battery consumption and portable. 3. Approved by strict quality and safety standards for long and trouble-free life. 4. Guaranteed high quality and accurate testing results. Description: Type: Gem Refractometer Measuring Range: 1.30-1.81 R Accuracy: ±0.002 Main Color: Black Weight: About 330g Size: 11 * 3 * 6cm Package Includes: 1 x Gem Refractometer 3 x Button Cell 1 x Oil 1 x English Manual Operating Information: 1. Open the upper cover then wash the gem and prism with alcohol. 2. Lay the instrument on the worktable. Drop a little bit of special refractive oil onto the surface of prism and press it by a thin glass bar. (Be sure not too much or too little) 3. Make sure the ground surface of gem to be measured is close to the prism, press it again lightly, let the refractive oil be evenly distributed between the two surfaces then close the upper cover. 4. Press the light momentary switch, make sure that the internal light source is turned on when testing. 5. Move the eyepiece up and down and adjust the diopter accordingly. By this time you can see a light/dark boundary in the viewing field. The gradation (shade) on which the boundary located is called the refractive index of gem. Notice: 1. Please understand the product might have some colour difference due to different monitors and scenes. 2. Please allow slight deviation for the measurement data.