Gem Research Swisslab — universally abbreviated in the trade as GRS — is an independent gemmological laboratory headquartered in Lucerne, Switzerland, with its principal operational facility in Bangkok, Thailand. Founded in 1996 by Swiss gemmologist Dr Adolf Peretti, GRS has grown into one of the most influential coloured-stone testing laboratories in the world, distinguished above all by its rigorous approach to geographic origin determination and its proprietary colour-quality designations, most notably pigeon blood for ruby and royal blue for sapphire. These designations, issued on GRS reports, routinely command measurable premiums at the world's leading auction houses and in the private high-end trade, making GRS documentation among the most commercially consequential paper in the coloured-gemstone market.

History and Founding Philosophy

Dr Peretti established GRS with a specific mandate: to bring scientific rigour to the determination of geographic origin in coloured stones at a time when the field was still heavily dependent on subjective visual assessment and the accumulated experience of individual gemmologists. The choice of Bangkok as the operational hub was deliberate. The city sits at the centre of the global coloured-stone trade, serving as the primary processing and trading hub for rubies and sapphires from Myanmar, Thailand, Cambodia, and Sri Lanka, as well as for stones transiting from East Africa and Central Asia. Proximity to the source and to the trade allowed GRS to build one of the most extensive reference collections of stones of known provenance in the world — a resource that underpins every origin determination the laboratory issues.

From the outset, Peretti positioned GRS as a research-driven institution rather than a purely commercial testing service. The laboratory has published extensively in peer-reviewed and trade gemmological literature, including Gems & Gemology, and has contributed original research on inclusion fingerprinting, trace-element geochemistry, and the spectroscopic signatures of specific deposits. This commitment to published science has been central to the laboratory's credibility with auction specialists, dealers, and collectors who require not merely a certificate but a defensible scientific opinion.

Scientific Methodology

GRS employs a multi-technique analytical protocol that is broadly consistent with the approach used by peer laboratories such as the Gübelin Gem Lab and SSEF (Swiss Gemmological Institute), though each laboratory maintains its own reference database and interpretive criteria. The principal techniques deployed at GRS include:

• Advanced optical microscopy and inclusion analysis: The systematic documentation of solid mineral inclusions, fluid inclusions, growth structures, and fracture patterns. Inclusions are often the most diagnostic evidence of geographic origin; a rutile silk of a particular morphology, a specific suite of secondary mineral inclusions, or a characteristic growth zoning pattern can point unambiguously to a single deposit.
• UV-Vis-NIR spectroscopy: Measurement of the stone's absorption spectrum across ultraviolet, visible, and near-infrared wavelengths. This technique is essential for identifying chromophores, detecting certain treatments (particularly heat treatment in corundum), and characterising the optical behaviour that underlies colour quality assessments.
• Raman and infrared spectroscopy (FTIR): Used to identify inclusion mineralogy, detect filler substances in fractures (glass, resin, oil), and characterise the host gem material itself. FTIR is particularly important in the detection of fracture-filling treatments in ruby and emerald.
• Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS): Trace-element analysis at the parts-per-million and parts-per-billion level. The trace-element chemistry of a corundum crystal — its ratios of iron, titanium, vanadium, chromium, gallium, and other elements — reflects the geochemical environment of its formation and can be highly diagnostic of geographic origin. GRS maintains proprietary databases of trace-element profiles correlated with specific localities.
• Energy-dispersive X-ray fluorescence (EDXRF): A non-destructive bulk chemical analysis technique used as a rapid screening tool and for certain species where surface chemistry is informative.
• Photoluminescence spectroscopy: Particularly useful for detecting certain treatments and for characterising the luminescence behaviour of chromium-bearing stones such as ruby and alexandrite.

No single technique is considered definitive in isolation. GRS, in common with other leading laboratories, bases its origin conclusions on the convergence of evidence across multiple analytical methods, weighed against the laboratory's reference collection and published geological literature on the relevant deposits.

Origin Determination: The Core Service

Geographic origin determination for coloured stones is among the most scientifically demanding tasks in applied gemmology. Unlike diamond grading, which operates on standardised scales against a relatively homogeneous material, coloured-stone origin determination requires the gemmologist to distinguish between deposits that may share the same mineral species, overlapping chemistry, and similar geological histories. The distinction between a Burmese ruby and a Mozambican ruby, or between a Kashmir sapphire and a fine Sri Lankan sapphire, is not always clear-cut, and reputable laboratories — including GRS — acknowledge that a proportion of stones yield inconclusive results.

GRS issues origin conclusions on a tiered basis. A definitive origin statement — "Burma (Myanmar), no indications of heating" — represents the highest level of confidence and carries the greatest market consequence. Where the evidence is consistent with a locality but not unambiguous, the report language is modulated accordingly. This transparency about the limits of scientific certainty is a hallmark of responsible laboratory practice.

The species for which GRS origin determination is most commercially significant include:

• Ruby: Burmese (Myanmar) origin, particularly from the Mogok Stone Tract, commands the highest premiums globally. GRS origin reports distinguishing Mogok material from Mong Hsu, Mozambican (Montepuez), Thai, and other sources are closely scrutinised at auction.
• Blue sapphire: Kashmir origin — from the Zanskar Range deposits discovered in the 1880s and largely exhausted by the early twentieth century — is the most coveted provenance designation in the sapphire market. GRS Kashmir reports, alongside those of Gübelin and SSEF, are considered essential documentation for stones offered at major auction.
• Emerald: Colombian origin, particularly from the Muzo, Coscuez, and Chivor mines, carries significant premiums over Zambian, Brazilian, and other sources. GRS employs fluid inclusion analysis (the chemistry of the primary fluid inclusions, which reflects the mineralising solution) alongside trace-element profiling for emerald origin work.
• Alexandrite and other chrysoberyl: Russian (Ural) origin alexandrite is historically the most prized; GRS has published research on the distinction between Ural material and alexandrite from Sri Lanka, Brazil, and East Africa.
• Spinel: Burmese spinel from Mogok, and more recently material from the Mahenge deposit in Tanzania, are subject to origin determination as the spinel market has grown in sophistication.

Colour Quality Designations: Pigeon Blood and Royal Blue

Among GRS's most commercially influential contributions to the trade are its proprietary colour-quality designations, which appear on certain reports as additional qualitative assessments beyond the standard origin and treatment conclusions.

The designation pigeon blood (Taubenblut in German, sang de pigeon in French) is applied to rubies that GRS determines to exhibit the specific combination of hue, saturation, tone, and fluorescence associated with the finest Burmese material: a vivid, pure red with a slight blue secondary hue, high saturation, medium-to-medium-dark tone, and strong red fluorescence under ultraviolet illumination that contributes to the stone's apparent glow in daylight. GRS has published its criteria for this designation, grounding it in colorimetric measurement as well as visual assessment. The designation is not exclusive to Burmese stones — GRS has issued pigeon blood designations on rubies of other origins that meet the colour criteria — though Burmese origin combined with the pigeon blood designation represents the apex of the ruby market.

The designation royal blue is the sapphire equivalent: a velvety, intensely saturated blue of medium-to-medium-dark tone, associated historically with Kashmir material but applicable to fine sapphires of other origins. GRS also uses the designation cornflower blue for sapphires exhibiting a lighter, more violetish blue associated with certain Sri Lankan and Burmese stones.

These designations are not universally used across all major laboratories. Gübelin and SSEF have historically been more conservative about issuing named colour grades, though market pressure has led to some convergence in practice. The commercial weight carried by GRS colour designations reflects both the laboratory's scientific reputation and the degree to which major auction houses — Christie's, Sotheby's, Bonhams, and Phillips among them — have incorporated GRS report language into their catalogue descriptions and pre-sale estimates.

Treatment Detection

Alongside origin determination, treatment detection is the other pillar of GRS's analytical work. The laboratory issues conclusions on the presence or absence of the following treatments, among others:

• Heat treatment in corundum: The most commercially significant treatment in the ruby and sapphire market. Unheated stones of fine quality command substantial premiums — often two to four times the price of equivalent heated material — because heat treatment is irreversible and near-universal in commercial-grade corundum. GRS uses a combination of inclusion alteration patterns (rutile silk dissolution, discoid fractures around inclusions, altered zoning), FTIR spectroscopy, and UV-Vis spectroscopy to assess heating status.
• Beryllium diffusion treatment: A lattice diffusion treatment introduced commercially around 2001 in which beryllium ions are driven into the corundum lattice at very high temperatures, dramatically altering colour. Detection requires LA-ICP-MS analysis, as beryllium is too light to be detected by EDXRF. GRS was among the first laboratories to develop and publish protocols for beryllium detection.
• Fracture filling in ruby: The impregnation of surface-reaching fractures with lead glass or other substances to improve apparent clarity. This treatment, widespread in lower-grade commercial ruby, is detected by FTIR and by microscopic observation of characteristic bubble structures and flow patterns within the filler.
• Fracture filling and oiling in emerald: Cedar oil, synthetic resins (Opticon, Permasafe), and other substances are routinely used to fill surface-reaching fractures in emerald, improving apparent clarity. GRS assesses the degree of filling and the nature of the filler substance.
• Irradiation and coating: Detected by a combination of spectroscopic and visual techniques as appropriate to the species.

Report Types and Documentation

GRS issues several categories of report, calibrated to the nature of the stone and the level of analysis requested. The full GRS Gemreport — the laboratory's flagship document — provides species identification, geographic origin conclusion, treatment assessment, and, where applicable, colour quality designation. It includes photographic documentation of the stone and, for significant pieces, photomicrographs of diagnostic inclusions. A shorter GRS Minilab report is available for smaller or lower-value stones where full origin determination is not required. GRS also issues GRS TypeII reports for certain species where a simplified format is appropriate.

The physical report is accompanied by a security hologram and a unique report number that can be verified through the GRS online database — a standard anti-fraud measure across the major laboratories. For stones of exceptional importance, GRS has collaborated with Gübelin and SSEF on joint reports, a practice that has been used for certain landmark auction lots where the combined authority of all three Swiss laboratories was considered commercially desirable.

Position in the Laboratory Landscape

The coloured-stone laboratory market is dominated by a small number of institutions whose reports are accepted without reservation at the highest levels of the trade. GRS occupies a position in this tier alongside the Gübelin Gem Lab (also Switzerland) and SSEF. A second tier includes the American Gemological Laboratories (AGL) in New York, the Asian Institute of Gemological Sciences (AIGS) in Bangkok, and Lotus Gemology, also in Bangkok. GIA's coloured-stone reports are widely respected but have historically been less focused on the nuanced colour-quality designations that drive premiums in the fine coloured-stone market.

GRS is particularly dominant in the Bangkok trade, where its physical proximity to dealers and its deep expertise in Southeast Asian material — Burmese ruby and sapphire above all — gives it a practical advantage. For Kashmir sapphire and Colombian emerald, the three Swiss laboratories (GRS, Gübelin, SSEF) are considered roughly co-equal in authority, and major auction consignors frequently obtain reports from more than one laboratory for stones of exceptional value.

The laboratory has also been active in publishing research on newly significant deposits as they enter the market — notably Mozambican ruby from the Montepuez deposit (which came to prominence after 2009) and Burmese spinel from Namya — contributing to the trade's ability to accurately characterise and price material from sources that were not represented in earlier reference databases.

Criticisms and Limitations

No laboratory, however rigorous, is immune to the fundamental limitations of origin determination as a discipline. The geological processes that produce gem corundum are broadly similar across many deposits, and the chemical and inclusion signatures of different localities can overlap. GRS, in common with its peers, has faced criticism on specific cases where its conclusions have differed from those of other leading laboratories — a phenomenon that reflects genuine scientific uncertainty rather than institutional failure, but which can create confusion and commercial disputes when two reports on the same stone disagree.

The commercial weight of GRS colour designations has also attracted scrutiny. Critics have argued that the pigeon blood and royal blue designations, because they carry direct price implications, create an incentive structure that is in tension with purely scientific objectivity. GRS has responded by publishing its colorimetric criteria and by emphasising that the designations are applied consistently regardless of origin. The debate is ongoing and reflects broader tensions in an industry where scientific assessment and commercial valuation are inextricably linked.

Further Reading

• Gems & Gemology — GIA's peer-reviewed journal, containing multiple articles on origin determination methodology
• GIA Research: Ruby Origin Determination
• Lotus Gemology Library — comparative laboratory methodology articles