Presidium Refractive Index Meter II (PRIM II) Digital Gemstone Tester | Wide Range 1.000–3.000 RI Measurement for Diamonds, Moissanite & Gem Identification | No RI Liquid Needed, Desktop Jewelry Tool — Open-Box, 31% Off

ACCURATE WIDE-RANGE GEM TESTING (1.000–3.000 RI | Measure refractive index across a broader range than traditional refractometers, allowing accurate testing of diamonds, moissanite, zircon, and a wide variety of colored gemstones.

FAST, CLEAN & LIQUID-FREE OPERATION | Eliminate messy RI liquids—get instant readings using advanced light reflectivity technology for quick and efficient gemstone identification and separation.

IDENTIFIES DIAMONDS & SIMULANTS INSTANTLY | Quickly separate diamonds, moissanites, and common simulants like strontium titanite using precise digital RI readings and built-in reference charts.

DIGITAL DISPLAY + BUILT-IN GEMSTONE DATABASE SOFTWARE | Clear LED display shows instant RI values, while included software features 50+ gemstones and allows filtering by color, hardness, SG, and more to identify unknown stones.

PROFESSIONAL DESKTOP DESIGN – EASY TO USE | Compact, lightweight tester with oval testing platform, blackout cover cup for accuracy, gemstone holder, and USB/battery power options—ideal for jewelers, gemologists, and collectors.

The Presidium Refractive Index Meter II (PRIM II) is a professional-grade digital gemstone tester designed to deliver fast, accurate, and mess-free refractive index (R.I.) measurements. Unlike traditional refractometers limited by narrow measurement ranges and the need for refractive liquids, the PRIM II offers a broad R.I. testing range from 1.000 to approximately 3.000—covering most gemstones available in today’s market. Using advanced light reflectivity technology, the PRIM II measures how light interacts with a polished gemstone surface to instantly determine its reflectivity, before converting it to the refractive index. This allows users to efficiently separate diamonds, moissanite, and other diamond simulants such as high zircon and strontium titanite, as well as identify a wide range of colored gemstones. Designed for ease of use, the PRIM II features a pinhole-sized light measurement system on a wide oval testing platform, along with a blackout cover cup to ensure accurate readings free from ambient light interference. Results are instantly displayed on a clear digital LED panel, with an integrated refractive chart for quick reference—especially useful for stones with RI values above 1.8. The included complementary software enhances identification capabilities with a gemstone database containing over 50 stones and their properties, including refractive index, hardness, specific gravity, color, and country of origin. Users can input known characteristics to narrow down and identify unknown gemstones through a process of elimination. Compact, portable, and efficient, the PRIM II requires no waiting time between tests and operates on a 9V battery or via USB power (adapter not included), making it ideal for jewelers, gemologists, appraisers, and gemstone enthusiasts seeking a reliable and modern testing solution.