Driving gemstone lovers to corundums. A twenty years tireless work for the most accurate survey on rubies and sapphires

26 October 2017

Recensione Ruby & Sapphires Hughes

R.W. Hughes, Ruby & Sapphire. A gemologist’s guide. Bangkok, Lotus, 2017

Let’s put it prosaically. Can you recall the first time you happened by a brand new model, let’s say, of a Mercedes? You wonder how could they still modify for the better what proved to be already a good car. Well, Richard W. Hughes made the grade. He has strengthened and updated a text that already set an international standard for those studying corundums. Since 1997, the year of its first edition, gemologists and traders keep considering this scrupulous work a classic, must-have publication. Yet the structure of the new book remains the same. It is composed of 12 chapters, each one scanning natural, treated, enhanced, imitated rubies and sapphires, under the powerful spotlights of historical, chemical, physical, geological and optical investigation.

At a first glance the reader realizes how much the world of rubies and sapphires has changed in the last twenty years. The author recaps how did this happen at page 240: “two events tipped the balance. The first was the development of beryllium diffusion…the second was…Mainland China”.

In fact at the beginning sapphires treated by deep diffusion of trace elements flooded the market in a quite deceptive way, at a time when the newly affluent but unskilled Chinese buyers showed up. They were alarmed by the increase of manipulations. As a consequence demand for true “natural” gemstones grew up and prices of unheated corundums skyrocketed. This provoked a great pressure on the market to achieve a better knowledge and more accurate quality reports for corundums.

Market changes and developments in the investigation technique during the last twenty years are mirrored by an increased amount of pages (734, i.e. 222 more than previous issue). The tough job did not require even a page less. This is because today better measuring instruments are available in support of researcher’s task of illustrating the phenomena with a wider collection of pictures and more effective tables. From a pure scientific point of view the most consistent contribution can be found in the accurate and updated catalogue of the frequently visited and screened mining sites in a so small scale that one may think that the author virtually passed across all the more significant mines.

The fourth chapter, “Color, spectra and luminescence”, is now definitely expanded in collaboration with an excellent team, John Emmett, Emily V. Dubinsky and K. Scarratt. A very close examination of the basic principles of spectrophotometry smoothly leads the readers (including those less familiar with the subject) to discover both the color bearing UV-Vis-NIR spectra of the many corundums and FTIR spectra useful to investigate heat treatments.

Well, while browsing the pages of the section related to treatments, the young gemologists are probably unaware that what the research nowadays takes for granted was just a not existing issue in 1997. This is the case of deep diffusion in the lattice. In the volume the subject is widely dealt with in the part reserved to high temperatures, whereas once just geuda from Sri Lanka stood out.

Appropriate and accurate asides enrich the technical accounts. Here one finds Hughes’ fine art made of apparent digressions flowing into streams of interesting tangent contents. The main thread of exposition offers first hand hints for additional considerations that would be lost elsewhere. One example for all. How could you do without Dick’s Law at page 212? Namely, the risk of finding fake rough increases proportionally to how close we are to the mining areas where the searched mineral is supposed to come from.

The images accompanying the volume are not only extensive but expressive, portraits are soulful. Hughes himself is an excellent photographer. He is able to return to the reader the powerful and revealing images of his many field expeditions (often in company of his never forgotten good friend, Dana Schorr). Likewise the group of young micro photographers (Nathan Renfro, Danny Sanchez, his daughter Billie along with veteran John Koivula) performs an outstanding work on inclusions.

As a matter of fact this book intends to be basically a work tool and a reference for researchers. The methodological approach for the purpose reveals the well known scientific personality of Richard Hughes. Any chapter focuses a particular gemological aspect from a different, peculiar point of view far from the stalemate of stiff positions. A sincere eclecticism animates the author’s effort to achieve the state of the art for every investigated subject, either reporting on the frequently visited mining sites or assessing at the best the physical data obtained with the same enthusiastic zeal of a nineteenth century positivist researcher. As such Hughes willingly seeks help from his excellent group of specialized colleagues obtaining comprehensive and fluid accounts of geological and chemical aspects. But looking deep down the background, a strong relation can be found between Ruby, Sapphires and the social context, this being a common feature in Hughes’ works. We (and our economies) are the final destination of the amazing journey of gemstones. Any gemological description would be meaningless if not inspired by desire, curiosity, vanity and passion of readers. Without portraying miners, traders, burners the all matter would be mere compilation. By this perspective Hughes, even though paying respect to fathers of gemology, clearly shows his heterodox way of thinking. It is sufficient to look at his “heretical” aversion to color grading systems and at his skepticism about the rush to determine the geographical origin of precious stones. Why should a researcher renounce to his point of view?

Richard Hughes - Ruby & Sapphire