RGM-100 Portable Gemological Refractometer Kit – 1.30–1.81 RI, 1.800 RI Fluid, Light & Gemstone Chart

Product description

Identify gemstones with greater confidence using the RGM-100 Portable Gemological Refractometer Kit from NI Supply. Designed for gemstone identification, gemology education, jewelry inspection, and laboratory applications, this compact optical instrument measures a gemstone's refractive index (RI) — a valuable property used by gemologists to help distinguish one gemstone from another.

This complete kit includes the RGM-100 refractometer, 1.800 refractive index contact fluid, illumination accessories, optical filters, a gemstone refractive index chart, and an easy-to-follow user guide written by NI Supply staff. Whether you are a jewelry professional, gemstone dealer, gemology student, or hobbyist building your testing toolkit, this package gives you essential equipment and educational resources to get started.

Why buy the RGM-100 from NI Supply? You receive more than the instrument alone. We include practical reference materials and our own beginner-friendly instructions to help you understand the equipment, take readings, and interpret your results.

Portable gemstone identification tool

Measures refractive index across a stated range of 1.30–1.81 RI, helping users compare unknown stones with established gemstone reference values.

Includes 1.800 RI contact fluid

A vial of 1.800 refractive index fluid is included for optical contact between a suitable gemstone surface and the refractometer prism.

Optical accessories included

The kit includes a polarizing filter, monochromatic light filter, and 789 nm light/torch accessory as specified for this package.

Learn with included reference materials

Receive a gemstone refractive index chart and a user guide with beginner-oriented instructions written by NI Supply staff.

Key features and benefits

• Broad refractive index range: Measures from 1.30 to 1.81 RI, covering the reference ranges of many commonly encountered gemstones.

• 0.01 RI scale divisions: Provides readable scale increments for comparing refractive index measurements.

• Portable design: Compact dimensions make it suitable for a gemology workbench, jewelry shop, classroom, or field kit.

• 1.800 RI fluid included: Helps establish optical contact between the gemstone and the measuring prism when used correctly.

• Polarizing filter: Supports examination of optical behavior, particularly when evaluating stones with different optical characteristics.

• Monochromatic light filter: Included to support the instrument's optical measurement procedure.

• 789 nm light/torch accessory: Included as specified for this RGM-100 package.

• Gemstone RI chart: Provides a reference for comparing readings with known gemstone values.

• NI Supply user guide: Written by our staff to make the instrument's operation easier to understand.

• Protective storage: Supplied with the stated black vinyl zipper case and hard case.

What can the RGM-100 tell you about a gemstone?

A gemstone's refractive index describes how light changes direction when it enters the material. Different gemstones have characteristic RI values, although some gemstones overlap in their ranges.

The RGM-100 allows the user to observe the optical reading through the instrument's viewing system and compare that reading with gemstone reference information.

Used properly, refractive index testing can help you:

• Narrow down the possible identity of an unknown gemstone.

• Distinguish between certain gemstones with different refractive indices.

• Support jewelry inspection and gemstone sorting.

• Compare readings from stones being evaluated for purchase, resale, or collection.

• Learn fundamental gemological testing techniques.

Important: Refractive index is one part of gemstone identification. Some natural gemstones, laboratory-grown stones, and imitations may have overlapping optical properties. Results should be evaluated alongside other appropriate tests, such as magnification, specific gravity, spectroscopy, or professional gemological examination when needed.

How a gemological refractometer works

The RGM-100 uses an optical measuring prism and viewing system to help determine a gemstone's refractive index.

Actual readings depend on the gemstone's surface, optical properties, contact fluid, illumination, and measurement technique. Follow the supplied operating instructions and use only surfaces and materials suitable for refractometer testing.

What's included with your RGM-100 kit?

Technical specifications

Note: The manufacturer-supplied specifications do not establish measurement accuracy, and the stated 0.01 RI graduation should not be interpreted as a guaranteed accuracy of ±0.01 RI.

Specifications of the included 1.800 RI fluid

The included contact fluid is specified for a refractive index of 1.800 at 25°C. It is intended to provide optical contact between a suitable gemstone surface and the refractometer prism.

Fluid handling and safety: Use the fluid sparingly and follow the applicable safety data sheet (SDS) and product instructions. Avoid skin and eye contact, do not ingest, and keep it away from children. Clean the prism and gemstone promptly using a method compatible with the instrument, gemstone, and fluid. Some gemstones, treatments, coatings, and porous materials can be damaged by contact fluids; do not assume every stone is suitable for this testing method.

The fluid's complete chemical safety information should be obtained from its supplier before publication of a comprehensive SDS-based safety statement.

Frequently asked questions

What is a gemological refractometer used for?

A gemological refractometer measures a gemstone's refractive index, an important optical property used in gemstone identification. Gemologists compare the result with reference values to help distinguish between possible gemstone identities.

Can the RGM-100 tell me whether a diamond or gemstone is real?

It can provide useful identification information, but it cannot conclusively authenticate every gemstone on its own. A refractometer reading should be considered alongside other gemological tests, particularly for diamonds, mounted stones, synthetic gemstones, and imitations.

Does this kit include refractive index fluid?

Yes. The advertised kit includes a vial of 1.800 RI contact fluid, described in the original product specifications as 10 grams and approximately 1.8 mL.

Is this suitable for beginners?

Yes. The package includes a gemstone RI reference chart and a beginner-oriented user guide written by NI Supply staff. Users should familiarize themselves with the instructions and appropriate safety precautions before testing gemstones.

What is the measuring range?

The stated range is 1.30–1.81 RI, with scale divisions of 0.01 RI.

What do the polarizing and monochromatic filters do?

They are optical accessories used to support the prescribed testing procedure. Their specific use depends on the instrument's optical design and instructions. They should not be considered substitutes for additional tests when a gemstone's identity is uncertain.

Can I use it on mounted jewelry?

Refractometer testing generally requires a suitable, accessible, flat gemstone surface that can make appropriate optical contact with the prism. Many mounted stones cannot be tested reliably because of limited access, surface geometry, or the risk of damaging the setting or stone. Consult a qualified gemologist when necessary.

Is the instrument ready to use out of the box?

The kit is supplied with the listed accessories, contact fluid, batteries, reference chart, and instructions. Follow the supplied setup and operating directions before taking measurements.

Why purchase from NI Supply?

At NI Supply / National Industrial Supply, we aim to make specialized measurement equipment easier to purchase and use. Our product listings emphasize practical information, included accessories, and useful documentation so customers can make informed purchasing decisions.

Whether you are equipping a jewelry business, expanding a gemology toolkit, studying gemstone identification, or looking for a portable refractometer for your laboratory, we are here to help you select equipment that fits your application.

For product questions, availability, or assistance, contact our team.

NI Supply — National Industrial Supply

30777 Rancho California Road, #891420 Temecula, CA 92589, USA

• Phone: 951-308-9269

• Fax: 310-733-5480

• Email: nisupply@gmail.com

• Website: www.nisupply.com

Please contact us with any questions about the RGM-100 or its included accessories before ordering.