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Gem Refractometer Gemology Gemologist RGM-100 w/ 789nm Flashlight RI 1.800

National Industrial Supply

  • $ 10499

Item Description: RGM-100 Portable Gemological Refractometer with a flashlight COMES WITH 10 Gram Vial (1.8ml) of  1.800 Index Fluid

Comes with instructions!  Written by our staff, not converted from another language!

Comes with a Gemstone Refractive Index Chart!

Comes in a black zipper case!


Product Specs:

Measuring Range :1.30 - 1.81 RI 
Minimum Graduation : (RI) 0.01 RI 
Dimension : 125mm x 70mm x 40mm
Scale Division : 0.01 nD 
Weight : 0.4 kg 
Ranges of Application : Laboratory, Gemology 
Power Source : 3 x AG13 1.5V button batteries
Light: Flashlight/Torch, 789nm Wavelength


One BRAND NEW RGM-100 Portable Gemological Refractometer in a Black Vinyl Zipper Case in a sturdy hard case. This handy little piece of equipment tests a gemstone's ability to slow down or bend light. The amount of slowing down it does to a beam of light is called the refractive index. THIS UNIT WILL HELP YOU DETERMINE WHICH GEMS ARE REAL AND WHICH ONES ARE FAKES! 



How does it work?: The refractometer works by the use of a glass hemicylinder inside that has a flat surface extending into the body of the refractometer. When light is introduced into the back of the unit, it travel through the glass hemicylinder and up to the gemstone, where the stone is in optical contact with the glass by use of a refractive index liquid. This liquid keeps air from between the stone and the glass hemicylinder and allows light to travel at the same speed through the glass, gets refracted by the gemstone, and then back through the glass hemicylinder to the viewing lens. The amount of slowing down or bending of the light that the gemstone does to the light beam, causes a light and dark area joined by a thin green line. This green line is the refractive index reading of the gemstone.


Included are:

****10 Gram vial (about 1.8ml) of 1.800 RI Fluid****

* Black Vinyl Soft case
* Polarizing Filter
* Monochromatic Light Filter
* Flashlight - 789nm

* Users Guide, BEGINNERS HOW-TO Guide


Specifications of 1.800 RI Fluid:

Refractive Index @ 25'C: nD = 1.800 +/- 0.005 @ 25°C
Appearance and color: Burgundy liquid
Boiling Point at 760 mm Hg:  181° C (358° F)
pH: Not applicable
Vapor Pressure: 760 mm Hg @ 23° C/73° F...1.5
Viscosity: Not applicable, but close to an ISO 5
Specific Gravity (water = 1) @ 23° C/73° F:  3.08-3.
Water solubility: Slight
Octanol/Water Partition Coefficient in Kow: Specific value not known
Flash Point: >230'F (110'C)
Evaporation Rate (mineral oil = 1, 760 mm Hg, 73° F/23° C): 1



For inquiries about this product, please contact me at the e-mail address below.

National Industrial Supply 
30777 Rancho California #891420
Temecula, CA 92589, USA
Sales: 951.308.9269
Fax: 310.733.5480  -  E-mail:  -  Website: