Gübelin Gemstone Rating

The Gübelin Gemstone Rating assesses the quality, rarity and salience of a specific gemstone and translates these attributes into a simple number: the Gübelin Points. It gives meaningful orientation for privates and for professionals who wish to get a comprehensive ranking for their gemstones, in particular as the trade and the consumers become more digital and cannot physically see and touch them.

So far, there is no common language to describe the key characteristics to communicate beauty, quality or rarity in a consistent way. The Gübelin Points intend to provide comparability and direction by reducing the complexity inherent to coloured gemstones.

Description

The Gübelin Gemstone Rating can be applied to the major types of high-value coloured gemstones. The rating procedure assesses different characteristics of the gemstone that contribute to its beauty, the rarity and the attractiveness.

The following types of gemstones are in scope:

  • ruby
  • emerald
  • sapphire (also fancy coloured sapphires)
  • padparadscha sapphire
  • paraiba tourmaline and rubellite
  • spinel (red-pink)
  • alexandrite and chrysoberyl
  • aquamarine, morganite and heliodor
  • demantoid, tsavorite and mandarin garnet
  • tanzanite
  • imperial, red-pink topaz

Only natural (i.e. non-synthetic) and transparent gemstones that are either faceted or polished qualify for the rating system. Gemstones which have been subjected to common treatments (e.g. traditional heating, clarity enhancement) can also be rated.

Rating aspects

The Gübelin Gemstone Rating comprises three domains: quality, rarity and salience.

Quality is the major part and covers the main visual characteristics of the gemstone, consisting of colour, clarity and transparency as well as cut and brilliance.

Rarity considers the relative availability of this type of gemstone in the market. It includes the gemstone variety, its size and the absence, presence and severity of treatment.

Salience addresses the extent of exceptionality and attractiveness of a gemstone beyond the objective characteristics of the quality category. It is best seen as the gemstone’s capability to stick out of the crowd.

The assessed characteristics yield an overall rating on a scale of 75 to 100 Gübelin Points. 

Gübelin Points Description
97.5-100 exceptional
95.0-97.4 outstanding
92.5-94.9 excellent
90.0-92.4 superior
85.0-89.9 fine
80.0-84.9 good
75.0-79.9 fair

 

Procedure

The rating is conducted by trained and experienced experts following standardised procedures. However, it is in the nature of any such rating to contain an element of subjectivity and vagueness leading to a limited repeatability of the result. Also, certain parameters shift and drift over time, and demands to adjust rating parameters such as the rarity from time to time. This also affects the consistency of the rating result.

It is also important to understand that the rating system is not exhaustive, and does not include all parameters that influence the commercial value of a gemstone. Hence, the Gübelin Gemstone Rating is not suitable to directly deduce buying or selling prices.

Fees

The standard fee for the Gemstone Rating service and issuance of a rating document, in combination with a standard Gübelin Gemmological Report, is CHF 100. Until end of 2021, we offer all Gemstone Rating requests coming along with our Gemmological Report for free.

The standard fee for the Gemstone Rating and issuance of a rating document in absence of a Gübelin Gemmological Report is CHF 250.

Order Form Lucerne
Order Form Hong Kong
Order Form New York

 

Limitations

If the Gemstone Rating is requested as a stand-alone service, i.e. in absence of a Gübelin Gemmological Report, the identity, treatment status and a possible phenomenon or trade colour are determined only by means of a microscopic analysis. This reduced and shortened level of analysis does not provide the level of certainty comparable to what is undertaken when testing a stone for a Gübelin Gemmological Report. Consequently, the identity, treatment status, phenomenon and/or trade colour of a specific gemstone might change when undergoing full testing, which in effect would also imply a different result in the Gemstone Rating.

FAQ

  • What are the parameters the Gemstone Rating is based on?

    The rating comprises the three domains of quality, rarity and salience. Quality describes the colour (hue, tone, saturation and homogeneity), the clarity and transparency of the gemstone as well as its cut and brilliance. Rarity considers the type of gemstone, the presence, absence or type of treatment, and the weight of the gemstone. Origin is not included in the rating. Additional points are granted for phenomenon and trade colour calls. Salience addresses the extent of exceptionality of a gemstone, it is best seen as the gemstone’s capability to stick out of the crowd.

  • Why is it all compressed to one figure?

    The world of coloured gemstones is a massive space. It consists of dozens of mineral species, hundreds of varieties, all imaginable hues and shades of colour, and a vast range of different gemmological and aesthetic traits and qualities. Treatments and origins multiply the complexity, as do gemmological phenomenon and certain local and regional preferences. To cope with this complexity is a challenge for professionals, and it is unmanageable for most privates. This makes coloured gemstones a demanding luxury purchase. The end consumer depends heavily on expert’s advice, and it is quite impossible to get even an approximate value-for-money. With the rating system, we intend to quantitatively assess some of the key characteristics of this space, and reduce the complexity by concentrating to a single figure. Thanks to this focus, the Gübelin Points give orientation in the complex world of coloured gemstones.

  • Why 75 to 100 points?

    Our rating system covers the upper part of the coloured gemstone realm. Low-value gemstones, very commercial qualities, crystals, rough gemstones, translucent to opaque gemstones, stones subjected to heavy treatments and synthetics are out of scope. The rating system is designed to handle the specific properties of the more high-end gemstones. To reflect that focus, the range of points is scaled to 75 to 100.

  • How do the points relate to commercial value?

    In connection with a report from a respectful gem lab, the Gübelin Points help to find the price. The rating system alone does not consider all aspects that influence the commercial value of a gemstone.

  • Why is origin not considered?

    The country of origin might have an ambiguous influence on the rarity or value of a gemstone. Historically, certain origins get related to superior properties such as a favourable colour. Examples of this are rubies from Burma, sapphires from Kashmir, and Colombian emeralds, which developed into actual brands and demanding a premium for their provenance. But such origin branding is controversial, and has hindered top qualities of gemstones from more recently discovered countries, lacking famous pedigree, to get the appreciation they deserve for their beauty and quality. Another ambiguity related to country of origin is the increasing importance of ESG criteria, referring to environmental, social and governance standards that are pursued differently in different places. For these reasons, we have decided to omit the country of origin as a characteristic for the gemstone rating.

  • Which gemstones are analysed?

    The rating is offered for most coloured gemstones of higher value, including ruby, blue sapphire and the most common fancy sapphires including padparadscha, emerald, spinel (red-pink), 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. non-synthetic), transparent and faceted or polished.

  • Why has Gübelin launched a gemstone grading system?

    To our knowledge, there is no comprehensive and easy-to-understand rating system for coloured gemstones in place. Especially consumers, but also the trade is looking for orientation into the complex world of coloured gemstones. With our almost 100 years of experience in seeing the best gemstones of the world, we believe we have a very robust base to establish such a system. Our gemmological laboratory has the credibility and the independence to offer the rating service. This rating service is open to the entire gem and jewellery industry. In a more digital world a rating makes it easier to select the right stone and allow a better comparison, even without having the gem in front. That helps the trade and the consumer.

  • What is special about the Gübelin Gemstone Rating?

    Our rating system combines comprehensiveness with simplicity. The system is fairly exhaustive regarding the visual quality of a gemstone, and it addresses the main aspects of rarity, another key trait of any gemstone. And finally it includes salience to express the exceptionality or appeal of a stone. All these key aspects are boiled down to one figure. This clarity of our rating system is unprecedented and awaited for specifically by consumers.

  • In what ways will this system change the jewellery industry?

    Since some years, the industry is already undergoing a change. Standardisation, formalisation and virtualisation are the response to changing expectations and habits of consumers. The current limitations to travel have only accelerated this trend. Our rating system is one tool that will help the industry to keep abreast with this development. It helps communicating within the trade, and with the final customer.

  • Is the rating only available with a Gübelin Gemmologial Report?

    The rating is also available without a report from the Gübelin Gem Lab. However, in combination with a Gemmological Report a gemstone has the best in class overall assessment, which allows for the highest peace of mind for the buyer.

  • Why is it called “Gübelin Points”?

    Points are ideal for rankings and assessments, think of school grades or wine ratings, as they provide comparability and give orientation in a comprehensive way. The late Dr Eduard J. Gübelin was known in the industry as an outstanding scientist, and he was equally admired by end consumers for his ability to communicate the beauty of gemstones to clients, explaining to privates how gems formed, and what makes them rare and exceptional. He combined scientific vigour and accuracy with a strong sense for the aesthetics of gemstones. When developing the rating system, we were also very much referring to the descriptions and texts of Dr Gübelin. Hence, the term “Gübelin Points” is not primarily referring to the Gübelin Gem Lab, or the House of Gübelin, but honouring the life and work of Dr Eduard Gübelin.

  • I have two different looking stones, but they have the same Gübelin Points. How is this possible?

    The rating system is based on a range of different criteria that get reduced to a single number. This implies that several paths can lead to a specific number. A less perfect, but rare stone might get the same points as a more abundant stone of higher quality. Even two gemstones of the same type, size, and treatment might get the same rating, although they look different: one might have a higher rating in colour, which the other compensates with a better clarity or cut rating.

  • Is the rating influenced by the personal taste and preferences of the grader?

    The rating system is based on the wealth of data the Gübelin Gem Lab has gathered on coloured gemstones over its almost 100 years of history and experience. This unique source of knowledge has allowed us to build the required structure and process to perform the rating with the best possible reliability and consistency. Our gemstone experts have to follow a strictly standardised procedure, supported by sophisticated tools and software for the assessment and evaluation of each rating criteria. This reduces the risk of a personal preference of the grader to a minimum. As with all services provided by the Gübelin Gem Lab, the client’s name gets removed from the gemstones before reaching the experts, i.e. they have no knowledge of the identity of the client, as this could also induce a possible bias.

  • Does the Gemstone Rating substitute a gemmological report?

    No. It is important to understand that Gübelin Gemstone Ratings are not based to the same level of scrutiny as Gübelin Gemmological Reports. In absence of a Gemmological Report, Gemstone Ratings are done on the basis of a short visual and microscopic assessment only, which does not comply with the standards specified by the Seal featured on Gübelin Gemmological Reports. Owed to this difference, the result of the short visual assessment applied for the Gübelin Gemstone Rating, and hence the resulting Gübelin Points, might not be consistent with the findings stated in a Gübelin Gemmological Report for the same gemstone. This is also why the Rating Document does not show the usual hallmarks of a Gübelin Gemmological Report, such as the hourglass background, signatures and the Gübelin Gem Lab Seal.

  • Is the Rating for a specific gemstone subject to change?

    The Gemstone Rating considers criteria such as rarity that are potentially undergoing change over time. This is best exemplified on rarity, which is directly influenced by supply and demand. Mining activity and the quality of mined stones changes, as do customer’s preferences. Consequently, rarity parameters need be observed, reviewed and possibly adjusted from time to time. The crux will be to find a balance between stability and consistency of the service on one hand, while reflecting the reality of the market (supply, demand, long-term trends) on the other hand. However, we do not intend to reflect fashions and short-term trends in our rating system.