1. Precision: This professional gem tester excels in quickly and accurately identifying single and double refracting gemstones, making it an essential tool for gemologists. With a measurement range of 1.30 to 1.81, it enables a wide variety of identification options. 2. Measurement Method: Apply a few drops of refractive oil onto the prism surface using a thin glass bar to determine if the gem is uniaxial or biaxial, whether it is photopositive or photonegative. 3. Refractometer Function: This diamond tester swiftly distinguishes between single and double gemstones, effectively identifying diamonds, moissanites, and colored gems, thereby speeding up gemstone identification with reliable results every time. 4. Reliable Performance: The jewelry refractometer features a clear display for easy readability. Its integrated light source and clear digital scale make it suitable for use in various environments.