M-Screen+ — HRD Antwerp's Automated Melee Synthetic-Diamond Screener
M-Screen+ — HRD Antwerp's Automated Melee Synthetic-Diamond Screener
An industrial-throughput tool for flagging suspect stones in melee parcels
M-Screen+ is an automated melee-diamond screening instrument developed by HRD Antwerp, the Belgian diamond grading laboratory affiliated with the Antwerp World Diamond Centre. The instrument is designed to process large volumes of small diamonds — typically 0.005 to 0.20 carats per stone — and to flag any stones that may be synthetic, treated, or otherwise of non-natural origin. Flagged stones are then sent for definitive analysis at a gemmological laboratory; the M-Screen+ does not itself issue identification verdicts.
The melee screening problem
Melee diamonds — small diamonds typically used as accent stones, pavé, and side-stone work in jewellery — present a particular challenge for synthetic-versus-natural identification. Individually inspecting each melee stone with the analytical instruments used for larger diamonds is time-prohibitive: a parcel may contain thousands of stones, and full spectroscopic analysis of each is not commercially viable. At the same time, undisclosed synthetic melee in jewellery has been a persistent industry concern since synthetic diamond manufacture became commercially scaled.
Automated screening fills the gap between the impossibility of full per-stone analysis and the unacceptability of doing nothing. A screening instrument runs each stone through a fast non-destructive test that reliably distinguishes the majority of natural diamonds from a smaller pool of suspect stones requiring further analysis. The pass rate of natural diamonds through screening should be near 100 per cent; the instrument's value rests on a low false-negative rate (synthetic stones not flagged) and a manageable false-positive rate (natural stones unnecessarily flagged for follow-up).
What M-Screen+ does
The M-Screen+ uses spectroscopic and luminescence analysis to evaluate each stone. Specific methodology details are proprietary, but the broader principle — common to all melee screening instruments including De Beers' DiamondView and SYNTHdetect, GIA's GemAnalyzer, and competing instruments from Yehuda and others — is that natural Type Ia diamonds (the majority of the natural diamond population) show distinct UV luminescence and absorption signatures from CVD- and HPHT-grown synthetic diamonds and from HPHT-treated natural diamonds.
The published throughput rate is approximately 3,600 stones per hour, with stones loaded as parcels into a hopper and progressed through the analysis chamber automatically. Output is a sorted result: stones cleared as natural pass to one bin, while suspect stones are diverted for further analysis. The throughput rate makes the instrument economically viable for parcel-level screening at a manufacturing or wholesale scale.
Position in the screening landscape
M-Screen+ is one of several commercial melee screeners. De Beers' SYNTHdetect and the earlier DiamondView are the most widely deployed across the industry. GIA's GemAnalyzer and the various academic and laboratory-developed instruments fill specific niches. The screening market has grown alongside the synthetic-diamond market and has standardised around the principle of automated first-pass screening followed by laboratory confirmation.
For users, the choice of instrument typically depends on existing laboratory affiliation, throughput requirements, and the size range of stones to be screened. M-Screen+ has a strong position among Antwerp- and European-based manufacturers and dealers and among operators with existing HRD relationships.
Limitations
No screening instrument is infallible, and all current commercial screeners produce some level of false-positive flagging. A diamond flagged by M-Screen+ as suspect is not necessarily synthetic — it may be a natural diamond with unusual luminescence properties (notably Type IIa naturals, which can be a small but real subset of the natural population). Flagged stones must be sent to a gemmological laboratory for definitive identification.
The instrument also does not screen for non-diamond simulants such as cubic zirconia or moissanite — those are caught by simpler thermal and optical tests, and parcels presented to M-Screen+ are typically pre-screened for simulants before melee-synthetic screening.
In the trade
For manufacturers, dealers, and retailers handling melee, automated screening has become a standard part of the supply-chain quality assurance protocol. Buyers of melee parcels increasingly require screening certification or perform their own screening on receipt. The cost of an M-Screen+ or comparable instrument has come down substantially since the early synthetic-screening generation, and the operational case for in-house screening is well established at any meaningful melee-handling scale.