GIA iD100
GIA iD100
Automated optical screening for diamond melee
The GIA iD100 is an automated diamond-screening instrument developed by the Gemological Institute of America to distinguish natural diamonds from laboratory-grown diamonds and simulant materials across the melee size range — nominally 0.003 to 0.20 carats. Using optical spectroscopy to detect characteristic absorption features associated with different diamond types and simulants, the iD100 can test up to twelve stones simultaneously and return a result in approximately one minute, making it one of the fastest screening tools available for high-volume trade use.
Purpose and context
The proliferation of laboratory-grown diamonds — produced by both high-pressure high-temperature (HPHT) and chemical vapour deposition (CVD) methods — has created a pressing need for reliable, rapid screening at the melee level. Individual stones in this size range are rarely submitted to a gemmological laboratory for full grading reports, yet they appear in their thousands in pavé settings, channel-set bands, and accent stones in finished jewellery. The iD100 was designed specifically to address this gap, providing manufacturers, wholesalers, and retailers with a practical first-line tool for verifying the integrity of melee parcels before goods enter the supply chain or reach the consumer.
Operating principle
The instrument employs optical spectroscopy — analysing the way stones interact with specific wavelengths of light — to identify absorption signatures that distinguish natural diamond from laboratory-grown material and from common simulants such as moissanite and cubic zirconia. Stones are placed in a testing tray and the process is largely automated; no individual stone positioning or operator spectroscopic expertise is required during routine use. Results are returned as one of two outcomes: a pass result indicating the stone is consistent with natural diamond, or a refer result indicating that the stone requires further examination by a more specialised instrument or a qualified gemmologist. The iD100 does not grade colour or clarity, and it does not issue grading reports.
Refer results and follow-up testing
A refer result does not confirm that a stone is laboratory-grown or synthetic; it signals that the iD100's screening criteria have not been satisfied and that additional testing is warranted. Stones flagged in this way are typically forwarded to GIA's DiamondCheck instrument or submitted to a gemmological laboratory equipped with more advanced spectroscopic tools — such as photoluminescence spectroscopy or Fourier-transform infrared (FTIR) spectroscopy — capable of providing a definitive determination of diamond origin and type classification.
Trade adoption
The iD100 has been adopted across multiple levels of the diamond trade. Diamond manufacturers use it to screen parcels of melee at source; wholesalers apply it before goods change hands; and retailers use it to verify finished jewellery, particularly items acquired on the secondary market or from unfamiliar suppliers. Its compact footprint and minimal operator training requirements have contributed to its uptake in settings where dedicated gemmological staff may not be present. The instrument represents part of a broader industry response — supported by GIA, the International Diamond Council, and major trade associations — to the challenge of undisclosed laboratory-grown diamonds in melee parcels.
Limitations
As a screening device rather than a definitive analytical instrument, the iD100 has inherent limitations. It does not provide stone-by-stone identification of every simulant type, and its refer category is intentionally conservative — designed to minimise false negatives (natural diamonds incorrectly passed as laboratory-grown) rather than to eliminate all refer results. It cannot be used as a substitute for full gemmological analysis when a definitive origin determination is required, such as in a legal, insurance, or high-value commercial context.