Presidium Refractive Index Meter (PRIM)

A light and portable instrument that instantly identifies diamonds, moissanites, and colored gemstones based on their Refractive Index.

By accurately measuring the quantity of light reflected through the gemstone, Presidium Refractive Index Meter (PRIM) is able to differentiate between diamonds, moissanites and other colored gemstones via their Refractive Index (R.I.).

Unlike a traditional refractometer, PRIM measures the range of R.I. value from 1.000 to ~3.000, covering most commonly known gemstones in the market, including diamond and moissanite. In additional, a fast and easy test can be done, without the inconvenience of R.I. liquid.


  • Clear and easy-to-read direct R.I. LCD display panel
  • International voltage compatibility
  • Battery-operated
  • Low battery indicator
  • Automatic power off
  • Portable and lightweight
  • R.I. Chart Reference included
  • Protective carrying case included
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Built-in reflectivity chart
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Testing pad

Dimensions and Weight

  • Length: 140mm (5.5 inches)
  • Width: 80mm (3.15 inches)
  • Height: 33mm (1.3 inches)
  • Weight: 140g (0.50lb)

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  • Identifies diamonds, moissanites, and gemstones instantly
  • Tests polished gemstones of any shape
  • Consistent and reliable results every time
  • Clear and visible display for ease of reading measurements
  • Light and compact tester that can be used anywhere
  • Simple and easy to use

Power and Battery

  • 9V batteries (up to 3 hours of continuous use based on alkaline batteries)
  • AC adaptor (optional item provided by Presidium)

Operating Conditions

  • Operating temperature: 18°C- 27°C (65°F- 80°F)
  • Storage temperature: 10°C- 50°C (50°F-122°F)

Technical Specifications

  • Dimensions: 140 x 80 x 33mm (5.5” x 3.15” x 1.3”)
  • Weight: 140g (0.50lb)
  • Power: 9V batteries or AC adaptor (optional item provided by Presidium)
  • Battery Life: Up to 3 hours of continuous use based on alkaline batteries
  • Visual Signals: Refractive Index (R.I.) value
  • Operating temperature: 18°C-27°C (65°F-80°F)
  • Storage temperature: 34°C-51°C (30°F-125°F)

Package Contents

  • Presidium Refractive Index Meter
  • Protective carrying case
  • User handbook
  • Warranty card

Optional Accessories

  • Presidium Universal Adaptor
Brass pins on vise
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Cylinder cover
Additional Information