Gübelin Gem Lab Seal

The gem and jewellery industry has, from the beginning, been built on trust and integrity. Gemmological laboratories play an important role in preserving transparency by helping the gemstone and jewellery trade – as well as the end consumer – to obtain the information needed to conduct business in a trustworthy manner.

Five main pillars

The Gübelin Gem Lab Seal is built on the following five main pillars. The requirements defined in these pillars must be followed in order to use the seal on any gemmological document.

  • 1) 6-Eye Principle

    Decision making of even the best-trained and most seasoned professionals is prone to errors. To mitigate the consequences of such possible errors by humans, redundancy principles are compulsory, i.e. critical work steps need be duplicated or even triplicated. Such measures reduce the impact of mistakes made by fallible humans. 

    6-Eye Principle at Gübelin Gem Lab

    Every gemstone must pass a minimum of three pairs of highly trained and experienced eyes during the testing process. Thus, each gemmological document featuring the Gübelin Gem Lab Seal combines the expertise of a minimum of three experts. To ensure that the different experts work as independently and unbiased as possible, the testing procedure is designed as such that any information about the client’s identity, and any possible conclusions drawn by preceding experts, are hidden. These measures intend to minimize the effects of a potential bias.

  • 2) State-of-the-art analytics

    The diversity of types of gemstones coming to a gem lab, the steadily increasing number of possible origins, and the more and more sophisticated procedures deployed to create synthetics and treatments pose a huge challenge to gem labs.  One prerequisite to cope with these complexities is the continuous investment in the latest analytical technology. A gem lab must have access to and make use of a very complete arsenal of the most advanced and sophisticated analytical equipment, machinery and processes emerging from various fields of science. It is a necessity to collect analytical data from different methods, i.e. comprising microscopic, chemical and structural properties. Only such a comprehensive analytical approach allows drawing the conclusions on a sufficiently robust set of data.

    These analytical instruments must be equipped with the required hardware and software accessories for testing gemstones. The calibration and testing methods and accessories, and the data collection routines must fulfil the highest professional standards. These testing facilities must be operated and maintained by trained and experienced professionals only (see also the fourth requirement pillar below), and the gathered data must be evaluated using the latest data evaluation methods. Most importantly, a gem lab must stay current through continuous research.

    State-of-the-art analytics at Gübelin Gem Lab

    The Gübelin Gem Lab stands at the forefront of gemmological research and makes use of the most advanced technologies in the field of chemical and spectroscopic analyses of gemstones. The intense use of various analytical technologies for the past decades has allowed the Gübelin Gem Lab to develop methods which serve as industry standards today. This can best be exemplified by the Laser Ablation ICPMS technology, which the Gübelin Gem Lab has started to use in 2002 for internal research, and eventually decided to apply it on client stones. Some 10 years ago, the Gübelin Gem Lab acquired its own LA-ICPMS system, and is happy to see that other gem labs are slowly following suit. A chemistry specialist with a broad background in chemical spectroscopy is in charge of the device and guarantees the most up-to-date application through continuous research. Furthermore, a spectroscopy specialist with a profound background in geology is in charge of the light absorption spectrometers and ensures the most recent practices.

    A significant part of the annual R&D budget is dedicated to the evaluation of new analytical technology and techniques. In cooperation with universities and manufacturers of equipment, we closely monitor the developments in the areas of earth sciences, chemistry, physics, material sciences and related fields, always striving for getting more and better information from the gemstones.

    As per 2015, access to the following analytical instruments are applied in the Gübelin Gem Lab for the reliable analysis of gemstones (basic gemmological equipment is not listed for the sake of simplicity):

    Microscopic analyses:
    • Dark-field / bright field gemmological microscopes, in combination with a powerful fibre optic light source

    Spectroscopic / structural analyses:
    • FTIR (Fourier transformed infrared) spectrophotometer
    • UV-VIS-nIR (Ultraviolet - visible - near Infrared) spectrophotometer
    • X-ray imaging system
    • Raman Spectrometer


    Chemical analyses:
    • ED-XRF (Energy dispersive x-ray fluorescence) spectrometer
    • LA-ICP-MS (Laser-ablation inductively-coupled-plasma mass-spectrometry)

    Each gemmological document featuring a Gübelin Gem Lab Seal is based on data gathered from multiple analytical methods. This rule adds to the robustness of the data collected on a gem, and must also be respected during Off-Premise-Testings.

  • 3) Empiricism

    One of the fundamental principles of science is the concept of empiricism, stating that conclusions must be based on empirical and measurable evidence, rather than assumptions or common beliefs. Hence, a gem lab has to draw conclusions on the identity, authenticity and origin of a gem i) solely based on objective, reproducible data acquired by lab staff, and ii) by comparing the properties of the unknown gemstone with those of known and secured provenance. This latter prerequisite implies the need for a reference collection covering all types of gemstones of commercial relevance, comprising all geographic origins, all possible treatments, and all types of synthetics and simulants. This collection has to cover both old – possibly closed or exhausted – sources, as well as the latest discoveries and inventions. Self-evidently, the number of stones of such a collection will add up to several thousands of stones. Only such a comprehensive reference collection provides a trustworthy and reliable basis on which the principle of empiricism can be properly applied.

    Empiricism at Gübelin Gem Lab

    At the Gübelin Gem Lab, we are working strictly along the principle of safeguarding our conclusions. The Reference Collection of the Gübelin Gem Lab comprises more than 25,000 gemstones from all the major sources and gemstone deposits around the globe - not only today's sources, but also from the past, from extinct and exhausted mines. Each sample is properly labelled, catalogued and described, its individual provenance and history are documented, and the level of authenticity is carefully assessed and rated. The Gübelin Reference Collection is carefully curated and continuously extended in order to maintain its relevance as a significant instrument within the gemstone testing process: it is an asset of incomparable value to the expertise of the Gübelin Gem Lab.

  • 4) Expertise

    The above-mentioned variety and complexity of gem materials that gem labs are confronted with today requires a knowledge going far beyond the level of gemmology, taught by any gemmological school.  Profound expertise in various disciplines of earth sciences is indispensible for the gemmologists working in a gem lab – especially when offering services such as the determination of colour authenticity in diamonds, origin determination in coloured gemstones, or the distinction between natural and cultured pearls.  
    The use of the sophisticated analytical equipment, and the proper evaluation of the collected data also demand elevated know-how and training from the operators. Times are gone where the requested skills and knowledge to master all individual tasks were combined in a single person. It is unavoidable to assign dedicated specialists to the individual tasks. The testing sequence a gemstone is subjected to in a modern gem lab needs be handled by a full team of specialists, each one focussing in his specific area of expertise. 

    Expertise at Gübelin Gem Lab

    The Gübelin Gem Lab puts great emphasis on education and training. The large majority of Gübelin Gem Lab gemmologists have earned a higher degree (M.Sc. or Ph.D.) in earth sciences, complemented with a solid gemmological training. Upon joining the team, each gemmologists undergoes a meticulous and rigorous internal training process, and can sign reports only after having successfully passed all required tests and exams, a process that typically takes several years to complete. This ensures a level of knowledge that goes far beyond all gemmological trainings available on the market.
    We believe strongly in the need for specialisation. Only when dedicated experts are assigned to individual parts of the complex analytical procedure, reliable data and trustworthy final conclusions can be taken (see also under 2) State-of-the-art analytics for a description of the analytical specialists).

  • 5) Ethical Guidelines

    Despite applying the most sophisticated technologies, the most stringent procedures, performed by the best trained experts, gemmology remains to be an inaccurate science, subjected to new developments and discoveries, limited by a permanently evolving base of knowledge, and prone to human and technical errors. Hence, ethical guidelines have to be defined that deal with these limitations, mitigating the effect of incomplete knowledge and of decisions taken by fallible and potentially suggestible humans.

    The above-described conditions and limitations have resulted in a Code of Conduct that serves as the ethical guideline along which the lab has to operate. The expertise represented through a Gübelin Gem Lab Gemmological Report stands for long-term credibility, accepting the borders of knowledge and therefore guaranteeing a most honest and sincere result. It is thus a document with the aim to protect the buyer of a gemstone or a jewellery piece by providing a professional and unbiased opinion completely independent from any trade activities.

    The Gübelin Gem Lab Code of Conduct

    1. Independence: The Gübelin Gem Lab is an independent legal entity. It operates independently from any trade or industry organisation. Its ownership and management structure are separate from any trade body.

    2. Confidentiality: The Gübelin Gem Lab's worldwide laboratory facilities are strictly protected by a rigorous access control. Access to the facilities and knowledge databases of the Gübelin Gem Lab is granted exclusively to personnel of the Gübelin Gem Lab.
    The Gübelin Gem Lab's laboratory and client database is strictly protected by specific access rights for selected members of staff of the Gübelin Gem Lab in order to protect the database from data breach or manipulation

    3. Limitations of knowledge: The Gübelin Gem Lab acknowledges the dynamic, progressing status of gemmological knowledge, and hence the fact that knowledge is limited at any given point in time. Consequently:
    • Only unambiguous and sufficiently robust data are regarded as adequate for a final conclusion on a Gemmological Report. If data are ambiguous or not sufficiently robust, no conclusions can be drawn
    • Insight gained from recent research is incorporated immediately and procedures are adjusted if required

    4. Abstinence from gem dealing: The Gübelin Gem Lab and its entire staff must not be involved in any commercial dealing activity, neither buying nor selling gemstones and jewellery. The procurement of samples for the reference collection, i.e. for pure research purposes, is excluded from this regulation. The Gübelin Gem Lab and its entire staff also defer from any appraisal services or brokering activities.

    5. Sharing knowledge: The Gübelin Gem Lab is committed to further the knowledge on gemstones, and to share the insights it has from its research and development activities with the academic community, the gemstone industry and the broader public.

The Gübelin family has been in the gem and jewellery business for more than 160 years and has always worked along strict professional principles. Ever since its establishment almost a century ago, the Gübelin Gem Lab has been pursuing the highest possible quality standards and refrained from making any compromises regarding analytical infrastructure, level of education and staff know-how as well as internal regulations and processes. Dr. Eduard Gübelin, an early pioneer in the analytics of gemstones, dedicated his life to search and share knowledge on gemstones, and thus creating transparency in the gemstone industry. Up to this day, his quest for knowledge, working attitude, and ethical standard serve as a role model for the Gübelin Gem Lab. To warrant and perpetuate his outstanding quality standards, the Gübelin family has imposed the Gübelin Gem Lab with its very own label - the Gübelin Gem Lab Seal. It stands as a quality hallmark outlining a set of guidelines that must be followed in order for it to be included on a gemmological document.

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