Gemological Refractometer Description

Gemological (Gemstone) Refractometer is your primary and most powerful tool in gemstone identification. As with a typical critical angle refractometer, it will measure the Refractive Index of faceted stones. Refractive Index is one of the most important optical parameters used to identify and authenticate polished precious and semi-precious gemstones. The 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). It comes with Refractometer Index oil, Mini Flashlight, Storage Box and Polarizing Lens. Have the most essential and powerful tool in identifying gemstones. Buy Now! Features: * Can identify gemstones quickly and accurately * Uniquely desigend, low battery consumption and portable * Powered by FREE four 1.55V Batteries * Approved by strict quality and safety standards for long and trouble-free life * Guaranteed high quality and accurate testing results * Brand new and unused Specifications: * Measuring Range: 1.30 ?1.81 RI * Minimum Graduation: (RI) 0.01 RI * Dimension: 30 x 70 x 130mm * Weight: 400g Accessories included: * Small Vial of 1.800 Refractive Index Oil (If you add USD12.00 to order, you will get a bottle of index oil in extra) * Polarizing Filter * Monochromatic Light Filter * Provides a unique Designed Mini Flashlight for illumination which includes the 4 1.55V(AG13) batteries * Storage Box * Refractometer Index Reference List (For 77 common gemstones, i.e. Calcite, Jadeite, Quartz etc.) * User's Manual Warranty: 2 years warranty Operating Information : * Lay the instrument on the worktable. Open the upper cover. Drop some of the special refractive oil onto the surface of the prism by a thin glass bar. * Make the ground surface of gem to be measured close to the prism, press it lightly to make refractive oil distributed evenly between the two surfaces and close the upper cover. * Align the entrance filter of refractometer and light source to the make luminance of viewing field even. * Move eyepiece up and down and adjust diopter appropriately. Now you can see a light/dark boundary in the viewing field. The gradation on the boundary shows the refractive index of a gem. * The index of double refractometer of gem can be measured precisely because the filter of the refractometer can eliminate the phenomenon of dispersion.