Gemstone Rating
The Gübelin Gemstone Rating assesses the quality, rarity, and attractiveness of a gemstone and translates these attributes into a single number: the Gübelin Points. The Gübelin Gemstone Rating offers end consumers and the entire industry meaningful guidance, transparent information, and comparison options.
The Gübelin Gemstone Rating is the first and most comprehensive methodology to evaluate the beauty, rarity and exceptionality of coloured gemstones. The Gübelin Points are easy to understand yet provide a competent assessment that fosters greater trust and confidence.
Description
The Gübelin Gemstone Rating is designed for precious coloured gemstones. It assesses the various properties of a coloured gemstone
that contribute to its beauty, rarity, and attractiveness.
The Gübelin Gemstone Rating is applicable for the following types of gemstones:
Ruby
Emerald
Sapphire (including fancy coloured)
Padparadscha sapphire
Paraiba tourmaline and rubellite
Spinel (red-pink)
Alexandrite and Chrysoberyl
Aquamarine, morganite and heliodor
Demantoid, Tsavorite and Mandarin Garnet
Tanzanite
Imperial Topaz (red-pink)
Only natural and transparent gemstones, which are either faceted or polished, qualify for the rating system.
Gemstones that have undergone standard treatments (e.g., traditional heating) can also be rated.
Rating Aspects
The Gübelin Gemstone Rating comprises three domains: quality, rarity and salience.
Quality is the most important factor and includes the most important visual characteristics of the gemstone, consisting of colour, clarity/transparency, cut, and brilliance .
The rarity rating takes into account the availability of this type of gemstone on the market. It also includes the type of gemstone, its weight, and any treatments it may have undergone.
Salience describes the special quality of the coloured gemstone that makes it stand out from the crowd.
Gemstones reaching 75 points or more qualify for a Rating Document.
Gübelin points
Description
95 - 100
exceptional
90 - 94.9
outstanding
85 - 89.9
excellent
80 - 84.9
superior
75 - 79.9
fine
Proceedings
The evaluation is conducted by trained and experienced experts according to a standardized procedure. However, it is inherent in the nature of such a rating that subjectivity and vagueness lead to limited reproducibility of the result. Furthermore, certain parameters shift over time and therefore require periodic adjustments to the evaluation parameters, such as rarity. This also affects the consistency of the evaluation results.
It is also important to understand that the rating system does not encompass all parameters that influence the commercial value of a gemstone. Therefore, the Gübelin Gemstone Rating does not allow for direct conclusions regarding the price or value of the gemstone.
Prices
For stones getting a Gübelin Gem Lab Report, the Gemstone Rating is included. For a stand-alone Rating service, i.e. without a Gem Lab Report, the standard fee for a Gemstone Rating is CHF 250.
Restrictions
If the Gemstone Rating is requested as a standalone service, i.e., without the Gübelin Gemmological Report, the identity, treatment status, and
any phenomena or typical trade colours are determined solely through microscopic analysis. This simplified examination is not comparable to the comprehensive
testing required for issuing a Gemmological Report and therefore does not offer the same level of certainty. Consequently, the identity, treatment status, phenomenon,
and/or trade colour of a particular coloured gemstone may change upon full analysis, which could also result in a different Gemstone Rating.
FAQ
On which parameter is the Gemstone Rating based?
The rating encompasses three areas: quality, rarity, and salience. Quality describes the colour (hue, depth, saturation, and homogeneity), the clarity and transparency of the gemstone, as well as its cut and brilliance. Rarity considers the type of gemstone, its weight, and whether it has been treated. Provenance is not factored into the rating. Additional points are awarded for the possible presence of special gemological phenomena and so-called trade colours. Salience refers to the exceptionality of a gemstone. It is best understood as the gemstone’s ability to stand out from the crowd.
Why is all of this compressed into a single number?
The world of coloured gemstones comprises dozens of mineral species, hundreds of varieties, every imaginable hue and shade, and a vast array of different gemological and aesthetic characteristics and qualities. Treatments and provenance further increase the complexity, as do gemological phenomena and specific local and regional preferences. Navigating this complexity is not only a challenge for professionals but also beyond the capabilities of most individuals. This makes coloured gemstones a demanding luxury purchase. The end consumer relies on expert advice, and obtaining even a remotely accurate price-performance ratio is nearly impossible. With this rating system, we aim to quantitatively assess some of the most important characteristics and reduce complexity by focusing on a single number. Thanks to this focus, the Gübelin points provide orientation in the complex world of coloured gemstones.
Why 75 to 100 points?
Our grading system covers the upper end of the coloured gemstone market. Low-value gemstones, average qualities, crystals, rough gemstones, translucent to opaque gemstones, as well as heavily treated and synthetic gemstones are not included. The grading system is designed to reflect the specific characteristics of high-end gemstones. To reflect this focus, the point scale ranges from 75 to 100.
What is the relationship between the points and the commercial value?
In conjunction with a report from a respected gemological laboratory, the Gübelin points system helps determine the price. However, the rating system alone does not take into account all aspects that influence the commercial value of a gemstone.
Why is the origin not taken into account?
The country of origin could significantly influence a gemstone’s rarity or value. Historically, certain origins have been associated with superior qualities, such as advantageous colour. Examples include Burmese rubies, Kashmir sapphires, and Colombian emeralds, which have become veritable brands, commanding a premium for their provenance. However, such origin labeling is controversial and has prevented very high-quality gemstones from newly discovered countries, lacking a famous pedigree, from receiving the recognition they deserve for their beauty and quality. Another ambiguity surrounding country of origin is the increasing importance of ESG criteria, which relate to environmental, social, and governance standards and are implemented differently in various regions. For these reasons, we have decided to omit country of origin as a criterion for evaluating gemstones.
Which gemstones are analyzed?
The rating is offered for most coloured, high-quality gemstones, including ruby, blue sapphire, and the most common fancy-colour sapphires, including padparadscha, as well as emerald, red-pink spinel, alexandrite, chrysoberyl, Paraiba tourmaline, rubellite, indicolite, tanzanite, aquamarine, morganite, heliodor, demantoid, tsavorite, mandarin garnet, imperial, and red-pink topaz. These types of gemstones qualify for the Gübelin Gemstone Rating as long as they are natural (i.e., not synthetic), transparent, and faceted or polished.
Why did Gübelin introduce a gemstone rating system?
To our knowledge, there is no comprehensive yet easily understandable grading system for coloured gemstones. End consumers, in particular, but also retailers, are seeking guidance in the complex world of coloured gemstones. With our nearly 100 years of experience with coloured gemstones, we believe we have a very solid foundation to establish such a system. Our gemological laboratory possesses the credibility and independence to offer this grading service. This service is available to the entire gemstone and jewelry industry. In an increasingly digital world, a grading system facilitates the selection of the right stone and allows for better comparison, even without physically seeing the gemstone. This benefits both retailers and end consumers.
What is special about the Gübelin Gemstone Rating?
Our grading system combines breadth with simplicity. It’s quite comprehensive regarding a gemstone’s visual quality and addresses rarity, another key characteristic. Finally, it also incorporates salience, which expresses a stone’s exceptionality or appeal. All these key aspects are reduced to a single number. This clarity of our grading system is unparalleled and is precisely what end consumers expect.
In what ways will this system change the jewelry industry?
The industry has been undergoing a transformation for several years. Standardization, formalization, and virtualization are the response to the changing expectations and habits of end consumers. Current travel restrictions have further accelerated this trend. Our rating system is a tool that will help the industry keep pace with this development. It facilitates communication both within the industry and with individuals.
Is the valuation only available with a Gübelin Gemmological Report?
The rating is also available without a report from the Gübelin Gemmological Laboratory. However, a gemstone receives the best overall rating when combined with a gemmological report, offering the buyer the greatest assurance.
Why is it called "Gübelin Points"?
Points are ideal for rankings and ratings; think of school grades or wine ratings, as they offer comparability and provide comprehensive guidance. The late Dr. Eduard J. Gübelin was known in the industry as an outstanding scientist and was admired for his ability to convey the beauty of gemstones to professionals and the general public, explaining how gemstones are formed and what makes them rare and exceptional. He combined scientific curiosity and precision with his keen sense of gemstone aesthetics. In developing the rating system, we also drew heavily on the descriptions and writings of Dr. Eduard J. Gübelin. Therefore, the term “Gübelin Points” does not primarily refer to the Gübelin Gem Lab or the House of Gübelin, but rather honors the life and work of Dr. Eduard J. Gübelin.
I have two gemstones that look different, but they have the same Gübelin points. How is that possible?
The grading system is based on a number of different criteria, which are reduced to a single number. This means that multiple paths can lead to a specific score. A less perfect but rare stone can receive the same points as a more common stone of higher quality. Even two gemstones of the same type, size, and treatment can receive the same grade, despite looking different: one might have a higher colour score, which the other compensates for with a better clarity or cut score.
Is the valuation influenced by the gemologist's personal taste and preferences?
The grading system is based on the wealth of data that the Gübelin Gemmological Laboratory has amassed over its nearly 100 years of history and experience with coloured gemstones. This unique source of knowledge has enabled us to establish the necessary structure and process to conduct grading with the highest possible reliability and consistency. Our gemologists adhere to a strictly standardized procedure, supported by sophisticated instruments and software for assessing each grading criterion. This minimizes the risk of personal bias on the part of the gemologist. As with all services provided by the Gübelin Gemmological Laboratory, the client’s name is not disclosed; that is, our gemologists have no knowledge of the client’s identity and thus remain impartial.
Does the Gemstone Rating replace a gemological report?
No. It is important to understand that the Gübelin Gemstone Rating is not based on the same level of examination as the Gübelin Gemmological Report. In the absence of a full gemmological report, gemstone valuations are based solely on a brief visual and microscopic assessment, which does not meet the standards of the seal displayed on our Gemmological Reports. Because of this difference, the result of the brief visual assessment, and the resulting Gübelin points, may not match the results given for the same gemstone in a Gübelin Gemmological Report. This is also why the valuation document does not display the usual features of a Gübelin Gemmological Report, such as the hourglass background, signatures, and seal.
Can the rating for a particular gemstone change over time?
The gemstone rating takes into account criteria such as rarity, which can change over time. This is best illustrated by the example of rarity, which is directly influenced by supply and demand. Mining activity and the quality of the extracted stones change, as do customer preferences. Consequently, the rarity parameters must be monitored, reviewed, and potentially adjusted from time to time. The crucial point will be to find a balance between the stability and consistency of the service on the one hand, and the realities of the market (supply, demand, long-term trends) on the other. However, we do not intend to reflect fads and short-term trends in our rating system.
The rating system does not take origin into account. Are you saying that origin is not important?
The reason for not considering origin as a characteristic for the Gemstone Rating lies in the ambivalence of origin, as explained in another Q&A (Why is origin not considered?). Nevertheless, we recognize that the provenance, and specifically the country of origin of a gemstone, remains important for the industry and the end consumer. For this reason, the Gübelin Gemmological Laboratory offers the determination of the country of origin in its gemological reports. Furthermore, the technologies and services offered by Provenance Proof provide an even more detailed insight into the exact origin of a gemstone. With the Provenance Proof Blockchain, we also provide a tamper-proof history along the entire value chain, from the mine to the end consumer, free of charge and for all types of gemstones and jewelry materials.
Does such a rating system reduce the gemstone to a commodity?
The world of coloured gemstones is vast and complex. Moreover, each gemstone is unique; no two gemstones look or are the same. This is what makes them so sought after by experts and consumers alike. Gemstones have, thankfully, always resisted commercialization. But this very heterogeneity and complexity also makes it difficult for consumers to navigate the world of gemstones. Our Gemstone Rating attempts to provide guidance by simplifying this complexity. Therefore, the rating system cannot tell the whole story of a gemstone, nor can it fully explain its beauty, appeal, and rarity. It is best viewed as a complement to and enrichment of the storytelling, rather than a replacement for it.
Given Gübelin's diverse activities, how does the Gübelin Gemmological Laboratory ensure an independent, neutral, and unbiased service?
Since its founding in 1854, the Gübelin company has been engaged in various activities. Initially, Gübelin sold and repaired watches, gradually expanding its product range to include jewelry. When Gübelin began creating its own jewelry, it wanted to know more about the gemstones it purchased and offered to its customers. At that time, knowledge about gemstones was largely confined to academia and not readily accessible to the industry. To learn more about gemstones and to live up to customer trust, Gübelin established a gemological cabinet, one of the first gemstone laboratories. Thus, in 1923, Gübelin opened its gemological laboratory, initially conducting internal gemstone testing for its own jewelry. From these beginnings, a solid foundation of gemological expertise developed, and eventually, the in-house laboratory began offering gemstone testing services to auction houses and the trade. At this point, Gübelin decided to spin off these activities into a separate company, a subsidiary, to prevent conflicts of interest. This step allowed the gemological laboratory to remain independent and offer its clients the necessary privacy. For many decades, we have had systems and procedures in place to ensure that all gemstones, regardless of who submits them, undergo the same testing and evaluation process. Client names and all other client-related information are removed before the testing process begins to minimize the risk of bias. We have established highly reliable systems to ensure that our gemologists see nothing but the stone while working. The gemological laboratory is a proud member of the Gübelin family, and we cooperate in certain areas, but definitely not when it comes to testing or now evaluating gemstones. The Gübelin Gemological Laboratory operates independently in its laboratory work and is not subject to any external influence when it comes to testing gemstones, nor do we grant any privileged access to the gemstones or orders we receive.
We are acutely aware of the challenges inherent in our corporate structure and have decades of experience managing and maintaining the necessary separation of systems, data, and responsibilities. It is this commitment to independence that ensures the provision of unbiased services and the protection and discretion of customer data. This is the foundation of the trust we have earned over time within the industry and among the public.
Why should a gemstone laboratory evaluate quality, beauty, and rarity?
Traditionally, the interpretation and explanation of quality, beauty, and rarity lay with the dealer or jeweler. Beauty is an essential aspect of coloured gemstones and a key characteristic for defining them. Ultimately, beauty is in the eye of the beholder, and no one can tell you what you personally perceive as beautiful. However, since beauty, and even more so quality, are also important factors influencing value and price, the shared and professional definition follows a certain logic and set of rules.
Gem labs have primarily focused on aspects based on scientific, analytical methods and concentrating on the material properties of gemstones. Traditionally, gem labs have worked with these science-based technologies and have continuously advanced their use to new applications. Our understanding of technology has also enabled us to address new challenges, such as bringing transparency to the gemstone supply chain. This has led to new services, the Emerald Paternity Test, and the Provenance Proof Blockchain; see www.provenanceproof.com for more information on these groundbreaking developments. And now we are once again leveraging technology and data to address another challenge related to gemstones: providing end consumers with guidance and orientation in the complex world of coloured gemstones. Based on decades of examining the world’s most exceptional gemstones, we have developed a comprehensive system and process for evaluating quality, rarity, and salience in a structured and reproducible way. By reducing these aspects to a single number, the Gübelin Points, we transform a highly complex topic into an easily understandable benchmark. This rating system shifts some of the interpretive authority from the trade to the end consumer. We believe this fosters trust among end customers and is therefore beneficial to the well-being of our industry. We also believe that a gemological laboratory, an institution not involved in the transaction of a stone, is well-positioned to assess the beauty and rarity of a particular gemstone from a more neutral perspective.
How is beauty defined?
While beauty is indeed in the eye of the beholder, some general assumptions can be made about the perception of beauty in gemstones. Rather than focusing directly on beauty, we are concerned with quality and salience. Looking at our data collected over many decades, the perception of quality appears to be based on a set of stable principles. As with all principles, there are exceptions, as they do not account for regional and local variations, let alone personal ones. Likewise, fashion and trends constantly alter these principles. Nevertheless, through decades of observing the gemstone industry and the privilege of seeing many of the highest-quality gemstones on the market, we have identified some principles or rules of thumb that we consider to be valid in the long term and globally. These include the understanding that the higher the transparency of a gemstone and the fewer inclusions visible to the naked eye, the better its quality. The more evenly and homogeneously the color is distributed across the stone, the better. And the more saturated and vivid a color is (i.e., saturation and hue are in harmony), the better (a well-known exception to this principle is padparadscha sapphires, where pastel shades are preferred over saturated colors). Other characteristics have an optimum, such as size, where larger gemstones are rarer and considered more valuable than smaller ones, but once the gemstone becomes excessively large, it may not fetch a higher price for that extra weight. Of course, the evaluation of size depends on the type of gemstone; that is, an 8-carat ruby is considered rarer than an 8-carat aquamarine. Other characteristics, such as hue, may not have a uniform ideal but allow for some variation. For example, topazes of different hues, such as red and orange, may be considered equally valuable and desirable. Generally speaking, pure…? Shades were considered more desirable than shades with a modifying color (Padparadscha, however, is a well-known exception that requires a mixture of both pink and orange shades).
Is salience subjective?
Compared to quality and rarity, salience is the parameter with the weakest quantitative or scientific basis. It contains an element of subjectivity, but it is based on a shared and general perception. In defining the quality criteria, we found that some gemstones possess characteristics that do not precisely match the parameters of a defined ideal, yet are highly attractive. Conversely, there are also some gemstones that fit well with what is considered ideal, but lack charm or appeal. There seems to be a common consensus among gemstone connoisseurs about which gemstones—beyond the objective quality criteria—are highly attractive and resonate with them. This shared perception led us to introduce the salience factor. This allows us, for example, to compensate for the lower rating given for transparency, which the typical Kashmir sapphire with its velvety appearance receives. Or for the lower rating given for color homogeneity in the most beautiful Padparadscha sapphires, which typically exhibit a slightly uneven colour distribution. And it also allows one to compensate for a gemstone that ranks highly in the more objective parameters of quality and rarity, but lacks visual appeal. Visual appeal may be subjective to some extent, but it is not accidental.
How does our service support the evaluation of a gemstone?
Information is key to evaluating a gemstone. Our range of innovative services and technologies can be combined to provide more information about various aspects of a gemstone, resulting in a clearer and more comprehensive understanding. These services complement and enhance each other, leading to a deeper appreciation of gemstones. The Gemmological Report offers a scientifically grounded opinion on the identity, authenticity, and provenance of a gemstone. The Gemmological Profile is a more comprehensive document that delves into the somewhat coded language of the Gemmological Report and includes additional background information on the type of gemstone, its geological history, and individual images of the gemstone’s interior. It also describes analytical details and provides insight into the microscopic, chemical, and/or spectroscopic data that the experts at the Gübelin Gemmological Laboratory have collected on that specific stone. Neither document makes a judgement on quality. That is the role of the gemstone appraisal. The overall assessment of the gemstone’s quality, rarity, and salience is expressed in Gübelin Points, which provide guidance and comparability for anyone buying or selling gemstones. While this assessment complements a stone’s description, it cannot fully explain or convey its value, beauty, and individuality. Furthermore, the Provenance Proof Initiative (details at www.provenanceproof.com ) offers a range of services utilizing state-of-the-art technologies to provide transparency regarding the exact origin and the entire supply chain. Our overarching goal is to offer a broad and comprehensive range of information that empowers buyers to make informed purchasing decisions based on reliable data from a trusted source.
