Cart 0

GEM Gemstone Refractometer Refractive Index Fluid 1.81 nD


  • $ 8499

Click Here. Double your traffic. Get Vendio Gallery - Now FREE!

Item Description: 3.6ml of 1.81 Refractive Index for Gem Refractometers, American Made, ARSENIC FREE!




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

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 3.6ml of fluid (so the vial ALMOST full!).  The big , factory sealed bottle only has 2.5ml (the 10 gram bottle)! 

This is the BEST deal for the money!

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
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.



Clearing the confusion (hopefully), here's a list of the products that we carry...

1.81 Refractive Index Fluid - this is the best fluid you can buy!

Size                       Volume of Fluid              Vial Price                 Price per 1ml
Small                           1.8ml                           $35.99                      $22.22
"10 Gram"                   2.5ml                          $59.99                       $24.00  <<----Not a good deal!

Economy Size              3.6ml                          $74.99                       $20.83

1.800 Refractive Index Fluid - this product will save you money with little compromise!

Size                        Volume of Fluid              Vial Price                 Price per 1ml
Small                            1.8ml                          $9.79                         $5.43
Economy Size               3.6ml                         $19.99                        $5.55

All of these items are available through the eBay Store at  Just type the words 'Refractive Index" and all of them will appear!


** Shipping **

Domestic S&H is $6.00 for (1) Vial, and an extra $1.00 per extra Vial.  For international shipments it is $15.00 ($12.00 to Canada) Air Mail via USPS (4-7 business days) and $1.00 for each additional Vial.

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


National Industrial Supply
30777 Rancho California #891420
Temecula, CA 92589, USA
Sales: 951.308.9269
Fax: 310.833.7306 

We prefer Paypal!  We accept Credit Cards via Phone, Fax or E-mail too!

We Also Recommend