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เริ่มเมื่อ 2012-11-03

Gemological (Gemstone) Refractometer with Built-in LED + Refractometer Index oil (GR-701)

ราคาพิเศษ 9,900 บาท

The GR-701, commonly known as Gemstone Refractometer, is the primary and most powerful tool in identify and authenticate polished precious and semiprecious gemstones and observing the optical properties and the structure of gemstones. This model is just as good as the expensive models used in gemological institutes. With the aid of Contact liquid (RI Fluid), that will create an optical contact between the glass and the gemstone, you can measure or test the Refractive Index of faceted stones, transparency or opacity, and its beauty, durability and scarcity. The refractive index (RI) of a gemstone provides the single most important piece of information to a gemologist seeking to identify an unknown stone. Due to its chemical composition and crystallization structure, each gem has a typical refractive index. In fact, you can also use this tool to measure R.I. for many minerals in crystal form as long as the crystals have a flat and polished face. Through these parameters, you can determine whether the gem is a Single Refraction (Isotropic) or Double Refraction (Anisotropic or Birefringence).

GR-701 offers you the worry-free, light and easy way to identify and/or authenticate your most precious gemstones.

  • Convenient & easy to carry
  • With built-in LED illumination that makes it a carry-and-use-it-anywhere device
  • Comes with Automatic Temperature Compensation (ATC) that let itself adjust to the climate
  • A bottle of Refractive Index Fluid is provided
  • Approved by strict quality and safety standards
  • Undoubtedly durable and very reliable


  • Measuring Range: 1.30 – 1.81 RI
  • Minimum Graduation (RI): 0.01 RI
  • Illumination: Internal LED illumination with momentary switch
  • Size: 35mm x 63mm x 115mm
  • Scale Division: 0.01 nD
  • Weight: 0.4 kg
  • Ranges of Application: Laboratory, Gemology
  • Filter: Polarizing filter
  • Power Source: 1.5V x3 button batteries

Operating Information:

  • Open the upper cover then wash the gem and prism with alcohol.
  • 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)
  • Make the ground surface of gem to be measured is close to the prism, press it again lightly, make refractive oil distributed evenly between the two surface. Then close the upper cover.
  • Press the Led momentary switch, make sure that the internal light source is turned on when testing.
  • 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.
    • Remove the polarizer. Turn it onto eyepiece. Then turn the polarizer lightly. You can only read the refractive index value in one direction at a time because the polarizer only allow the light vibrated in one direction to pass through.
    • Then turn the polarizer through 90°, you can measure the refractive index value of the light vibrated at right angles to that mentioned above.
    • Turn the gem in the same direction through small degree then turn the polarizer lightly according to above method, you can read the two refractive index values of the light vibrated at right angles to each other.
    • Operate continuously until the gem is at 180°position to its none position. From a number of groups of measured refractive index values you can find the maximum and minimum refractive index. The difference between the two values is the birefringence of gem.


  • After measurement, remove any dirt from the refractometer's housing (casing) then clean prism and the gem with alcohol to remove the refractive oil on it.
  • Put back the refractometer into the box for protection.
  • Remove the Battery from the Battery compartment if you are planning on not using the Refractometer for a long period of time to prevent leaks or molds that can damage your device.

Accessories included:

  • Small Vial of 1.800 Refractive Index Oil
  • Polarizing Filter
  • 1.5V x3 button batteries
  • Pouch Case
  • Refractometer Index Reference List (For 77 common gemstones, i.e. Calcite, Jadeite, Quartz etc.)
  • User's Manual

Packaging:  Pouch Case

The Product




Included: Refractometer Index Reference List
i.e. Jadeite Refractometer Index : 1.660 - 1.680
Reflective Index on PRM / PDT : 32 - 36


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