Presidium Gem Computer Gauge (PGCG)

A convenient digital gauge that measures actual gemstone dimensions and estimates gemstone weight and identity.

Presidium Gem Computer Gauge measures the dimensions and estimates the weight of loose and mounted gemstones with precision, speed, and ease. After entering the weight and the measurements of a gemstone, PGCG narrows its identity by computing its S.G. value.

With PGCG’s computer interfacing, gemstone measurement records can be easily imported and printed. PGCG also comes with a CD-Rom that lists the S.G. value, R.I. value, and hardness measurements of 133 common gemstones in the market for handy reference.


  • Measures from 0.0 to 25.0mm
  • Accuracy: 0.01mm / Tolerance: 0.02mm
  • Digital mm/ct display
  • Automatically shut off when idle for 10 minutes
  • Auto-magnetic shut-off when placed in carrying case
  • Computer interface display with CD and USB (Universal Serial Bus) connectivity
  • Attachment for high setting jewellery provided
  • Specific Gravity (S.G.) dictionary for quick and easy reference included
  • CD-ROM containing information on 133 gemstones (e.g., S.G. value, R.I. value and hardness) included
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Smooth slider mechanism
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USB connectivity

Dimensions and Weight

  • Length: 97mm (3.82 inches)
  • Width: 61mm (2.4 inches)
  • Height: 16mm (0.63 inches)
  • Weight: 120g (without battery)
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  • Measures actual gemstone dimensions and estimates gemstone weight and identity
  • Measures 74 gemstones and 9 different shapes
  • Accurate measurement to 0.01mm
  • Direct carat conversion for round brilliant-cut diamonds
  • Clear and visible display for ease of reading measurements
  • Light and portable instrument that can be used anywhere
  • PC connectivity for ease of importing and printing measurement results

Power and Battery

  • 1 x CR-2450 3V battery (about 80 hours of continuous use)

Measurement Range

  • 0.00mm to 25.00mm or 0.000ct to 57.343ct* (based on round brilliant cut)

Package contents

  • Presidium Gemstone Computer Gauge
  • CR-2450 3V battery
  • High setting jewellery attachment
  • Mini CD ROM
  • USB Cable
  • User handbook
  • Warranty card
  • Protective box
Brass pins on vise
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PGCG package
Additional Information