ASDI Diamond Spotter
ASDI Diamond Spotter
De Beers' automated spectral screening instrument for melee diamond parcels
The ASDI Diamond Spotter — an acronym for Automated Spectral Diamond Inspection — is a rapid-screening instrument developed by De Beers to distinguish natural diamonds from laboratory-grown material within parcels of melee-sized stones. Addressing one of the most practically challenging problems in modern diamond grading, the instrument processes large numbers of small calibrated diamonds at speed, flagging individual stones that require more detailed gemmological examination.
The screening problem it solves
The proliferation of laboratory-grown diamonds produced by both high-pressure, high-temperature (HPHT) and chemical vapour deposition (CVD) methods has created a disclosure and detection challenge that is particularly acute at the melee scale — typically stones under approximately 0.20 carats. Individual gemmological testing of every stone in a parcel of hundreds or thousands of such diamonds is economically and practically impractical using conventional instruments such as spectrophotometers or photoluminescence systems that require one-at-a-time specimen handling. The ASDI was designed specifically to collapse this bottleneck.
Operating principle
The instrument analyses the absorption spectra of each stone across multiple wavelengths using proprietary optical and algorithmic methods developed within the De Beers Group. Natural diamonds exhibit characteristic spectral signatures — including absorption features associated with nitrogen aggregation states and other lattice defects — that differ systematically from those of HPHT- or CVD-grown material. The ASDI's algorithms compare each stone's spectral response against these reference profiles and assign a result: either a pass (consistent with natural diamond) or a referral flag indicating that the stone warrants further testing by a qualified gemmological laboratory.
Importantly, the ASDI is a screening instrument, not a definitive identification tool. A flagged stone is not thereby confirmed as synthetic; it is identified as requiring the more rigorous analysis — such as photoluminescence spectroscopy or infrared absorption spectroscopy — that a laboratory such as the GIA Gem Laboratory or the International Gemological Institute (IGI) would apply.
Throughput and trade application
The instrument's principal commercial value lies in its throughput. Melee parcels can be fed through the system in bulk, with each stone receiving an individual spectral assessment in a matter of seconds. This makes it viable for use at the manufacturing and wholesale stages of the diamond supply chain, where parcels may contain thousands of stones and where the cost of laboratory certification for each individual melee diamond would be prohibitive. The ASDI is positioned as a first-line tool for manufacturers, dealers, and retailers who handle significant volumes of small diamonds and need confidence that their parcels have been screened before goods reach the market.
Context within the broader screening landscape
The ASDI sits alongside a growing suite of melee-screening instruments that have emerged in response to the synthetic diamond challenge, including the GIA iD100, the De Beers DiamondView (which uses short-wave ultraviolet fluorescence imaging), and the Gemological Science International (GSI) Sherlock Holmes system. Each instrument uses somewhat different physical principles and is suited to different operational contexts. The GIA has published guidance on the use of such screening devices and their role within a responsible testing protocol, noting that no single screening instrument should be treated as a substitute for full laboratory analysis when a definitive natural-versus-synthetic determination is required.