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GEM Gemstone Refractometer Refractive Index Fluid 1.81 nD


  • $ 4299

Item Description: 1.8ml Vial of 1.81 Refractive Index for Gem Refractometers (this vial is about HALF full - the 3.6ml $74.99 - is for a FULL vial)

American Made and ARSENIC FREE!


This product is the non-poisonous version of the classic Gem Refractive Index Fluid; Diiodomethane (methylene iodide). 

This product is also made in the USA!




The most important aspect of the Refractometer is the quality of the fluid and its Refractive Index. This product has a Refractive Index value of 1.81RI and is THE best product for accurate GEM Identification. 

The 4.0ml vial has an applicator rod inside the cap for easy application and holds 1.8ml of fluid.  The "10 Gram Vial" only has about 2.5ml! 

This is a better deal!

The Gem Refractometer Liquid has a refractive index of nD = 1.810, the highest of any liquid not containing arsenic. As the name implies, it is widely used with gem refractometers as a contact medium for the identification of gemstones. This light yellow liquid can also be used to reduce or eliminate glare from a gem's surface, facilitating inspection of the gem's interior for inclusions and other defects.

This liquid is supplied by a highly reputable American supplier in bulk and repackaged in an amber glass bottle. The cap has a plastic applicator rod attached to it on the inside, designed to deliver a small droplet.

To ensure the liquids maximum shelf life, keep this liquid tightly sealed after opening, store it away from direct light and in moderate temperatures.



Refractive Index @ 25'C: nD = 1.81 +/- 0.005 @ 25°C
Appearance and color: Golden liquid/Burgundy when exposed excessive heat/light
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:  3.14
Water solubility: Slight
Octanol/Water Partition Coefficient in Kow: Specific value not known
Melting/Freezing Point: 20°C (68°f)
Evaporation Rate (mineral oil = 1, 760 mm Hg, 73° F/23° C): 1

This product is the non-poisonous version of the classic Gem Refractive Index Fluid; Diiodomethane (methylene iodide).  It is not carcinogenic according the the product MSDS.



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

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