DiamondSure is an automated gemological screening instrument developed by the International Institute of Diamond Grading and Research (IIDGR), the laboratory and instrument division of De Beers. Using ultraviolet-visible (UV-Vis) absorption spectroscopy, it rapidly distinguishes natural diamonds from laboratory-grown stones — whether produced by high-pressure high-temperature (HPHT) or chemical vapour deposition (CVD) methods — and from simulant materials such as moissanite and cubic zirconia. The instrument is designed as a first-stage, high-throughput screening tool: it delivers a result in seconds and is widely deployed by grading laboratories, including the GIA, as well as by manufacturers and trade buyers who need to process large parcels of melee efficiently.

Operating Principle

DiamondSure analyses the UV-Vis absorption spectrum of each stone and compares the result against a reference database of known natural diamond spectra. Natural type Ia diamonds — by far the most common variety encountered in commerce — display a characteristic absorption profile arising from aggregated nitrogen defects. Stones whose spectra deviate from this profile, or that lack the expected nitrogen-related features, are flagged with a refer result, indicating that the specimen requires confirmatory analysis by a more discriminating instrument or a trained gemmologist. Stones that pass are issued a pass result, indicating spectral consistency with natural diamond origin.

It is important to note that a pass result does not constitute a certificate of natural origin; it indicates only that the stone's absorption characteristics are consistent with a natural diamond and that no anomaly warranting referral was detected. A refer result similarly does not confirm synthetic or simulant status — it triggers the next stage of investigation.

Practical Specifications

DiamondSure is designed for loose stones of approximately 0.18 carats and above, the lower threshold reflecting the minimum mass required for reliable spectral acquisition. Mounted stones cannot generally be tested, as the setting may interfere with the optical path. The instrument requires no sample preparation and is non-destructive. Testing is completed in a matter of seconds per stone, making it practical for parcel screening in a trade or laboratory environment.

Role in the Screening Workflow

DiamondSure occupies the first tier of a two-stage screening protocol that has become standard practice in responsible diamond laboratories. Stones that receive a refer result are subsequently examined using more sophisticated instrumentation — most commonly DiamondView (also developed by De Beers IIDGR), which uses short-wave UV fluorescence imaging to reveal growth structure, or spectroscopic systems capable of photoluminescence (PL) and infrared (IR) analysis. Together, DiamondSure and DiamondView form a complementary pair: the former provides rapid, high-volume triage; the latter provides definitive structural evidence of growth origin.

The GIA's melee screening service, introduced in response to growing concern about undisclosed laboratory-grown diamonds entering mixed parcels, incorporates DiamondSure as part of its detection workflow. The instrument's speed and ease of use make it particularly valuable in this context, where hundreds or thousands of small stones may require evaluation.

Limitations

DiamondSure is not infallible as a standalone tool. Certain natural type IIa diamonds — colourless or near-colourless stones with very low nitrogen content — may generate a refer result because their spectra differ from the type Ia norm, even though they are entirely natural in origin. Conversely, the instrument is not designed to detect all possible treatments applied to natural diamonds, such as fracture filling or some forms of colour enhancement. Its function is specifically the natural-versus-laboratory-grown and natural-versus-simulant distinction at the screening stage, not comprehensive quality or treatment analysis.

Industry Context

DiamondSure was introduced commercially in the early 2000s, at a time when HPHT-treated and HPHT-grown diamonds were beginning to appear in the trade in meaningful quantities. Its development reflected De Beers's dual interest in protecting the integrity of the natural diamond market and in providing the broader trade with practical detection tools. The instrument has since become a de facto industry standard for first-stage screening, and its widespread adoption has contributed to the normalisation of systematic diamond verification as a routine trade practice rather than an exceptional measure.