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Professional Gem Refractometer Plug-In - Easy to Read


  • $ 19999

RGM-PLUG - 1.31-1.81nD Range Plug-In Gem Refractometer


FINALLY!  A plug in Refractometer that will give you consistent light!  No more batteries and the no more bad light that comes from weak batteries!

THE PLUG IN LIGHT SOURCE ALLOWS FOR A CONSTANT PERFECT STREAM OF LIGHT!  It is the easiest Refractometer to read on the market!

Comes with easy to follow instructions in English!  Written by our staff, not converted from another language!

Comes with a Gemstone Refractive Index Chart!

Comes with 3.6ml of 1.800 Refractive Index Fluid - DOUBLE THE AMOUNT FLUID THAN OTHER SELLERS!


Range: 1.30-1.81 Refractive Index (RI)
Resolution: +/- 0.01 RI
Accuracy: +/- 0.01 RI
Dimension: 4.5" x 1.5" x 2.5"
Weight: 400 Grams
Composition: Sturdy, Portable Design made of die cast aluminum, not plastic like the GIA ones
THE LIGHT SOURCE: 36” inch corded 110 volt plug at 789nm.  The light source will not become hard to read when batteries grow weak!  It is a constant bright light!

Perfect for the GIAStudent, Hobbyist AND Professional!
This item is an exceptional Value!  Quality Unit, Right RI Fluid!


The BRAND NEW RGM-PLUG Portable Gemological Refractometer comes in a Black Vinyl 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! 



This unit is helpful in Testing for Cabochons, as well as, testing for Double Refraction!

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.

Competitively Priced!


This type of unit sells for $795.00 and up at most retailers. Get yours today at Wholesale prices!

Included are:
* Black Vinyl Soft case
* Polarizing Filter
* Monochromatic Light Filter
* Internal light - Standard wavelength 589nm - runs off 1.5 volt button cell batteries (included)
3.6ml Vial of 1.800 Refractive Index Oil (Amazon Gem Refractometers only come with 1.725RI Fluid - A HUGE GAP THAT RENDERS YOUR RESULTS FLAWED!)  <----No One else does this for new units!
* Users Guide, BEGINNERS HOW-TO Guide



The RGM-PLUG comes with a 5 year warranty against any defects, so you can buy with total confidence.  This unit is made of die cast aluminum and has a smooth finish.  It is not made of plastic like the $600 units out there! 

A deal is only a good deal if the quality is excellent and the seller is still around after the sale for any questions you may have!



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: 310.748.6858
Fax: 310.733.5480  -  E-mail:  -  Website:

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