Gemmological Nomenclature vs Scientific Nomenclature

Gemmology studies the materials that are set in jewellery (with the exception of metals) which are also study subjects of other disciplines, like mineralogy, geology or biology, where there are well defined nomenclatures and specific lexicons. Should gemmology strictly follow academic rules or should there be a tolerance in the nomenclature used in the gem and jewellery industries?

The famous Hutton-Mdivanni necklace: for a geologist, there are 27 drilled beads of jadeitite, a metamorphic rock from the blue schist facies; for a gemmologist there are 27 drilled beads of jadeite jade or even "imperial jade" © Sotheby's

The so called "gem materials" that are used in jewellery and objects d'art come from a variety of materials, including minerals, rocks, fossils, biogenic substances, organic substances and a wide range of artificial products (e.g. synthetic stones, composite stones). Every natural or artificial substance in these groups are, to a lesser or greater extent, object of study of diverse disciplines that include mineralogy (e.g. minerals: diamond, quartz, topaz), petrology in its magmatic, metamorphic or sedimentary sub-disciplines (e.g. rocks: lapis lazuli, aventurine quartz, jadeitite), palaeontology (e.g. fossils: ammolite, amber), zoology (e.g. pearl, shell, coral), botany (e.g. corozo, copal), solid state physics (e.g. artificial products: cubic zirconia, synthetic sapphire), among many other possible scientific approaches. There are, therefore, academic fields of expertise that produce science and knowledge that is communicated with very specific rules and nomenclature accepted by the scientific community. This research data, usually published in peer reviewed papers in scientific journals, is often too complex for the non-scientist to fully understand and appreciate. The complexity of modern gemmology, in an increasingly convergent route with science, has been behind the increasing complexity of the articles published in gemmological journals (e.g. The Journal of Gemmology, Gems & Gemmology) that is a challenge for the editors since their audience is mostly composed of professionals of the gem and jewellery industry, not members of the scientific community, requiring reader friendly formats.

Early Gemmology and Science 

Gemmology, as a discipline, emerges in the late 19th century as response to the needs for consumer confidence and product knowledge in the jewellery industry, namely in the identification of precious stones and their substitutes. An advertisement in 1893 announces a six lecture course on "Gemmology, or the Science of Gems" in London, being probably on of the first structured educational events on record. The use of the word "science" might, however, be understood as a marketing strategy to introduce credibility on such a new subject. It is curious to note that the first gemmological diplomas in Europe were named "Mineralogy for Jewellers", issued by the National Association of Goldsmiths in London in 1911. The title reveals the need for adaptation of a scientific discipline to a consuming product driven industry. It also shows that in the early days of gemmology as a systematic branch of knowledge, the expertise and contribution of members of the Earth sciences community was paramount to its development, a reality that still stands today.

The jewellery industry produces, promotes and ultimately sells jewellery to the public, an activity that goes way back in time. Gem materials, as products and leading players in this decorative art, were historically categorised and named via interesting empirical knowledge.   In this historical context, many trade names have been used and reused through both verbal and written tradition in the various local vernaculars and languages throughout the globe. Only occasionally, did these names emanate, for example, from the Earth Sciences community that experienced significant advancements only in the 18th-19th centuries. Gemstone designations were pretty much associated with visual characteristics like colour (e.g. sapphire, chrysolite, aquamarine) and texture (e.g. agate, aventurine) or with commercial provenance (e.g. turquoise, tanzanite) in a very informal, sometimes romantic, way. The name "balas ruby"  as a purported ruby from Balas, is a good example. In reality, these red gems are spinels and they mostly came from the Kuh-i-Lal region in the Pamir mountains in today's Tajikistan, a region historically known as Badakshan, hence the Balas or Ballas designation. Famous examples include the Timur Ruby, the Black Prince Ruby and other Mughal period polished drilled beads.

Red spinels from the historical Badakshan region in today's Tajikistan were known as "balas" or "balas rubies". The 11 Mughal period spinels on this necklace are good examples on display at the Museum of Islamic Art in Doha, Qatar  © Christies

In those days, nomenclature was not much of a problem, since these designations intended to communicate products, not study materials, to a rather limited and strict elite in a period when science was not developed enough nor strong enough to inspire an industry to set standards. The inheritance of naming traditions is on the base of many of the current trade names, which are currently scrutinised as acceptable or not-acceptable by trade organisations. These organisations play a key role in setting consistent standards to promote and maintain confidence among consumers that have greatly expanded to a massive audience of global proportions. In this scrutiny, science is taken into consideration as the gemmological community today has a considerable knowledge background, but tradition and consumer protection are also considered, bering in mind that nomenclature in the jewellery industry is there to serve the consumer.

Modern gemmology and Science

It is important to underline that Gemmology is not, strictly speaking, a science. In spite its foundations in scientific knowledge, gemmology began as a systematic set of methods to positively identify and classify gem materials in consumer products. Among the first challenges of the early gemmologists was the detection of flame fusion synthetic rubies in the dawn of the 20th century and the identification Akoya cultured pearls to separate them from the much more valuable natural pearls in the 1920's. Gemmology, therefore, established protocols and non-desctructive methods for the identification of the materials that were used in jewellery and in objects d'art, from the simple paste (glass) to the more valuable diamond.

Basil Anderson (1901-1984) was a leading figure in early gemmology as head of the Pearl, Diamond and Precious Stone section of the London Chamber of Commerce in 1925 where gem materials were identified at the service of the jewellery industry. © The Journal of Gemmology, Gem-A

It is also crucial to emphasise that gemmologists have consistently strengthen bonds with the scientific community due to several reasons: the advancements in earth sciences, solid state physics and biology; the evolution of technology in both treatments, crystal growth, pearl farming and analytical instrumentation; the increasing number of gem materials and new locality sources; the consumer demand for information on specific issues that are considered pertinent to gauge the perceived value of gem products (e.g. treatments, modern synthetics, geographic origins), among other developments. That can be easily demonstrated in the afore mentioned gemmological periodicals where the complexity of the information that is offered to the reader in peer reviewed articles is sometimes hard to digest for the average practicing gemmologist. The increasing number of PhD graduates and research fellows in various fields of expertise (not only mineralogy) in the staff of the more advanced and well prepared gemmological laboratories around the world also demonstrate the seriousness of the matters at hand. The cost of setting up a modern gemmological laboratory is now massive, namely in acquiring and maintaining the complex instrumentation needed to face the more delicate challenges (e.g. LA-ICP-MS, SIMS, LIBS, PL Spectroscopy, X- ray Tomography) and to build up data-bases based on samples collected in-loco on the various mine sites.

The cutting edge GemTOF system at the SSEF Laboratory in Basel, Switzerland, that enables very accurate critical analytical data to study gem materials. It is basically an enhanced LA-ICP-MS (Laser Ablation- Inductively Coupled Plasma - Time-of-Flight - Mass Spectrometry). This is the kind of advanced and complexed technology that is put at the service of modern scientifically educated gemmologists © SSEF

Setting Nomenclature Standards

These paragraphs served to demonstrate that, today, gemmology and science work hand in hand more than ever to serve an industry that promotes and sells products with the mission of maintaining consumer confidence. But the nuclear focus of this essay is nomenclature and, in light of this gemmology-science compromise, the question is if trade nomenclature should follow the strict academic framework or should it follow a more relaxed vision, sometimes romantic by tradition. Or is it both. 

CIBJO - The World Jewellery Confederation, is the foremost global authority in the jewellery industry and has released trade standards in the famous "Blue Books", available at

In the majority of cases, the names of gem materials generally accepted in the trade are the basically the same as in geology or in mineralogy (e.g. diamond, malaquite, topaz, obsidian). In some cases, though, the correspondence is not so accurate and occasionally there are discrepancies. This has led many academics in the gemmological world to question the accepted trade names and to insist on the use of strictly scientific terminology. To balance both views, the market's and the Academia's, CIBJO - The World Jewellery Confederation has played a vital role in setting standards with the utmost objective of defending consumers from ambiguous nomenclature, promoting their confidence on the jewellery industry and hence protecting the industry itself. These standards, published in the regularly reviewed "CIBJO Blue Books" (Gemstone Book, Diamond Book, Pearl Book, Coral Book), not only address best practices (e.g. treatment disclosure procedures) but also list the acceptable trade names and relates them to the science behind them. The members of the CIBJO commissions that produce these standards are typically members of the gemmological community (e.g. producers, dealers and research or laboratory gemmologists) and are therefore technically capable to discuss those matters in the best interest of the consumer and the trade, offering common sense to the desirable balance between the rigid scientific nomenclature of materials and the more simple trade nomenclature of products. Let's bear in mind that consumers don't have scientific background to fully appreciate the arguments behind the attribution of terms and are much more fond of the simple terms that are traditionally used as vernaculars in the market across the globe.

"Organic gems"

Let's see some examples where nomenclature issues are a challenge if we abide by strict scientific rules. In the case of biogenic gem materials, traditionally called organic gems, like pearls and corals, for example, the correct way to address them is to point out the living organism that originated them using the binomial terminology, or taxon names, used in biology. The trade does not refer to these gem materiais using taxa names, but rather vernaculars that vary in different geographic areas where they are harvested. For example, the precious coral known in the trade as "magai", "boké" (two Japanese terms), "angel's skin" (an English term) or "pelle d'angelo" (an Italian term) correpsonds to the rare flesh pink varieties of the Plaurocorallium elatius, a deep water coral species that lives in certain areas off the coast of Japan and Taiwan. This species also produces precious coral with different colours that circulate in the trade under different names (e.g. momo, cerasuolo, satsuma). Another example, the so called Fiji cultured pearls in the trade correspond to the pearls that are cultivated in the Fiji pearl mollusc  Pinctada margaritifera var. typica (Linnaeus 1758) off the coast of Savu Savu in Fiji.
It is not hard to understand that simple trade names communicate better that the complex and often long scientific designations. CIBJO, in this respect, has been played a key role in the scrutiny of all the trade names, relating them with their scientific significance, and contributing to consumer confidence as it can be seen in the Pearl Book and Coral Book.

A strand of graduated beads of light pink precious coral from Pleurocorallium elatius known in the trade by many names, including "angel's skin", "boké" or "magai". © Chii Lih Coral


In mineralogy, the normative body is IMA, the International Mineralogical Association, that publishes regularly a list of accepted mineral names, but in gemmology there is some tolerance in the use of obsolete or non-accepted names in modern mineralogy. An example is "iolite" that is an obsolete designation to a mineralogist for the mineral "cordierite", but that is regularly used in the trade to communicate that purple gem mineral. The same with "marcasite", that is used in the trade for the pyrite small rose cut stones that were popular in silver jewellery of the 1930's. Marcasite is a mineral name of its own for a totally different material than the used in the jewellery industry. Both "iolite" and "marcasite" are accepted trade names, although they can be considered technically incorrect in light of scientific standards, but tradition has played an important role in this.
Another interesting case is tourmaline. With all accuracy, tourmaline is not a mineral species, but rather a vast mineral group composed of borosilicates of similar structure and complex variational composition. The names of tourmaline species vary according with their composition and designations like schorlite, dravite, elbaite, fluor-liddicoatite, rossmanite, uvite, ferro-uvite, foitite, buerguerite, among many others, are well known to mineralogists. Most of these terms are also familiar to gemmologists. In the trade, however, we hardly see a gem tourmaline being named by their scientific designation. Gem tourmalines are mentioned using a colour descriptor and sometimes a colour related trade name like, for example, pink tourmaline or rubelite, blue tourmaline or indicolite, green tourmaline or verdelite. Other trade names like watermelon tourmaline (concentric bi-colour with pink in the interior and green in the exterior) are also accepted. The chemical related nomenclature of tourmalines is not the main argument for setting their trade names and let's focus on pink tourmaline, or rubelite, to make a point. Most of these are elbaites (a sodium and lithium rich tourmaline species), as are most of the gem tourmalines in the market, but both fluor-liddicoatite and rossmanite also have been reported in pink colour. In the trade floors, however, only the word "rubelite" or "pink tourmaline" is used to describe them.
We could also discuss the Paraiba tourmalines that, up until recently, have been considered elbaites with blue to green "neon" or "electric" colours of medium to strong saturation due to copper/manganese that occur in Brazil, Nigeria and Mozambique. The high value of these gems and the multiple communications, articles, blog posts or social media publications, has made the term "cuprian elbaite" quite familiar to the more curious reader. It happens that fluor-liddicoaties of similar visual characteristics in the "paraiba" range have recently been reported. All the above mean that the complexity of mineral terminology is significant and that it is quite simplified when it comes to the trade. Moreover, the proper identification of a mineral species in the tourmaline group and their causes of colour sometimes requires advanced instrumentation and it is usually only performed in the paraiba type samples due to their high value that justify the analysis.

A fine cut 6,11 carat pink tourmaline or rubellite. Does it make sense to call it a pink elbaite, fluor-liddicoatite or rossmanite? © Clear Cut Gems


More interesting examples can be discussed around the names used to designate the jades. Jades are rocks, not minerals, and geologists call these petrological materials very different names than the professionals on the jewellery industry. Jade is a curious name that comes from a 16th century Spanish expression “piedra de ijada” that was given to nephrite jade from China (the French reportedly translated it to “pierre de l’éjade” and it evolved to “pierre de la jade”, and then “jade”). When the Spanish recovered “piedra de ijada” artefacts in central America (made by Olmecs, Mayas, Toltecs and Aztecs), science was not yet aware that it was not the same material as the one that came from the Orient and bevause of that, the same name became to describe both. This went on until the 19th century when “jade” was separated into two groups: nephrite jade (essentially amphiboles - actinolite-tremolite series) and jadeite  jade (pyroxenes, essentially jadeite and/or omphacite). Mesoamerican jadeite jade from Guatemala is petrologically closer to Burmese jade, discovered in the 18th century, than it is to the traditional Chinese nephrite jade (and also from Russian, Canadian or New Zeland sources). Today, jade is a trade name used for two rocks: one of amphibolitic composition and one of pyroxenitic composition. The famous Hutton-Mdivani necklace featuring 27 fine quality beads of jadeite jade from Myanmar (formerly Burma) ranging from 15,4 to 19,2 mm featured at the beginning of this article is a fine example of a metamorphic rock from the blue schist facies known as jadeitite by geologists and as jadeite jade, or imperial jade, to gemmologists.


It is rather tempting for a mineralogist or academic to review all the gemstone trade names in light of the accepted scientific nomenclature and support changes with rather solid arguments. In spite of the scientific accuracy behind such arguments, it must be realised that the materials used in the jewellery trade are not only study materials in the various applicable sciences but also consuming products with a history and a tradition. These products should have unambiguous trade names that fully represent them along the distribution pipe-line, with special acknowledgment of their background by the sales professionals that ultimately communicate those products to the consumer. Here common sense must prevail and a reasonable balance between scientific nomenclature and trade tradition as been worked out as a trade standard by CIBJO in the Blue Books that are constantly being reviewed and updated. In the several CIBJO Blue Books (diamonds, gemstones, pearls and corals) accepted trade names are clearly presented (with treatment disclosure indications when applicable), leaving little room for ambiguity. One may ask is the rules unanimous and the answer is: not quite. They reflect the best judgment of the national and trade delegates of the World Jewellery Confederation that continuously promote discussion on those matters to regularly update and review the standards. These, however, already served in court cases.
Again, the bottom line is common sense and unambiguous, transparent and ethical practices, recognising and accepting that there is a tolerated difference between science and communicating a product in a consumer driven industry.

High-end jewellery, like this bracelet designed by José Manuel Rosas, feature gem materials that are communicated with accepted trade names (diamonds, multi-coloured sapphires and emeralds). © Rosior