Testimonials

Didier Giard,
Président de l'Association Française de Gemmologie

Voici la nouvelle édition de Dureté 10: le Diamant...
La parution précédente faisait le point sur la reine des gemmes dans une période économique d'inflation générale mondiale, après deux crises pétrolières et la malencontreuse spéculation qui avait jeté des doutes sur la valeur même du diamant.

Une nécessaire explication s'impose à nouveau aujourd'hui, alors que le diamant est devenu un cas modèle de la mondialisation. En deux décennies, il a supplanté l'or comme pivot de la joaillerie qui désormais s'articule autour du diamant devenu valeur référence. Dureté 10, le terme parle de lui-même. Il exprime la plénitude, le total, l'ultime, tout en témoignant des caractéristiques physiques, optiques, chimiques, thermiques et mécaniques inégalées du diamant.

Cette nouvelle édition enrichie, retravaillée, fait la somme de toutes les connaissances actuelles et des importantes évolutions qui ont eu lieu ces vingt dernières années.
En ce sens Dureté 10 est un livre de référence, il s'adresse aussi bien à tous les professionnels, experts, étudiants, qu'aux amateurs éclairés et à tout lecteur en quête de compréhension et de recherche de sens. Par sa clarté et son étendue, Dureté 10 a sa place dans toute bibliothèque.

Pour ce travail indispensable il fallait un homme complet comme Eddy Vleeschdrager.
Fin connaisseur du brut, de toutes les techniques de taille et des circuits de distribution du diamant, il est l'auteur de nombreux articles et livres reconnus. Il ajoute à cette palette de savoirs sa pratique de juge et d'expert international, ainsi que sa vaste expérience d'homme public acquise au sein de divers syndicats d'Anvers, du H.R.D., ou actuellement à la tête de la prestigieuse Guilde du Diamant et des Pierres Précieuses, créée en 1582 à Anvers.

De très nombreux lecteurs francophones connaissent les relations privilégiées qu'il entretient avec la France - où d'ailleurs il est né. Ils attendaient avec impatience la réédition de Dureté 10, tout comme l'Association Française de Gemmologie qui distribue de nombreux livres ayant trait aux gemmes. Dureté 10 figure chaque année parmi ses meilleures ventes. Dans cette époque où tout prend un sens uniquement financier, Dureté 10 nous invite à une communion avec la matière, celle qui, au-delà du visible et du quantifiable, véhicule la beauté de notre monde par l'émotion, la sensualité, la passion.
En ce sens ce livre joue le rôle de passeur, de transmetteur d'un héritage. Il nous permet d'appréhender dans l'instant la vraie éternité du diamant.

Didier Giard
Président de l'Association Française de Gemmologie

h.r.h. Prince Jean of Luxembourg

This year the 3rd edition of “Hardness 10” will appear. Since 1985 this book has become the standard reference book for the diamond industry to the point that it is considered to be of encyclopaedic value and reference work for the industry.

The author, Eddy Vleeschdrager, covers all aspects of the diamond : history, trade, scientific information, techniques, valuations and every aspect associated with this magic stone which reflects thousands of human adventures. In diamonds man meets nature. From the rough diamond to the finished jewel which it becomes, it embodies all the talents and knowledge of mankind : his work and knowledge, his imagination and creativity, his business acumen and his sense of beauty.

Antwerp, the cradle of diamond cutting since the fifteenth century and indisputably the centre of the diamond industry, has seen other dynamic diamond trading and cutting centres appear. The Guild of Diamond and Gem Cutters was founded in 1582 following the cutting techniques of Louis de Berquem and has since developed as promoter of the Antwerp diamond industry. It has organized international conferences in Antwerp, Paris and Marrakech and tirelessly continues its promotion activities.

This book, written by its late Chairman, provides the reader an insight into this industry which, like many other industries, has experienced a spectacular evolution over the last decennia. Modern technology in the study of carbon, the basic material of diamonds, has enabled the industry to utilize carbon molecules or atoms in nanotechniques and make spectacular advances in the field of medicine and in conquering space.

For the first time ever synthetic diamonds have appeared in quantity on the market and have been used in jewellery. How will the public react ? Diamonds are being manipulated by different techniques in laboratories, are they under control ? “Hardness 10” deals with these important questions.
The book appears at a crucial time in history :

• The sector has not seen such a grave crisis since the 2nd World War.
• Some mines are depleted, while others have only just been discovered.
• New producing countries have appeared whereas others ceased.
• De Beers, the major producer of the twentieth century, has changed its distribution policy.
• Rio Tinto, Alrosa and Dominion have become the new actors in the industry.
• Canada has become one of the most important producing countries.
• China has become a cutting centre and an important consumer.
• Dubai known as a centre for jewellery and gold is becoming a diamond centre.
• These troubled times for diamond industry have caused some people to regret the period when De Beers “controlled” the rough market.

Since the first edition of this book the cutting techniques developed over many centuries have ventured into the 21st century, a phase of spectacular automatization using lasers and computer programs which are becoming more and more sophisticated.
The time when wholesalers came to Antwerp for their supply of polished diamonds have changed. The diamond dealer has to adapt his “business model” and, for instance, participate with the jeweller, visit his clients and utilise modern communication tools such as the internet.

This book will give the reader (whether he be producer, jeweller or diamond amateur) a complete overview of this fascinating gem and its spectacular history.
I hope that you will have as much pleasure as I had in reading this book.

h.r.h. Prince Jean of Luxembourg

Stéphane Fischler,
President Antwerp World Diamond Centre
Vice-President of the World Diamond Council

For centuries, ours has been an industry in which the knowledge, the expertise, the craftsmanship and passion for one of nature’s most precious gift, diamonds, were things that were almost exclusively passed on from one generation to the next.

Becoming a cleaver, sawyer, polisher or diamond trader was something of a birthright, something one learned from grandfathers, fathers and uncles, starting at the very bottom of the ladder, working all the way up the various stages through the fascinating journey of a rough stone, transformed by skilled hands into a perfect, brilliantly polished diamond. Sons and nephews were initiated into the captivating complexities of our trade through hard work, trial and error.

When “Hardness 10” was first published, now three decades ago, it was the first work of reference that – literally – covered every facet of the business, assembling decades of knowledge in what is rightfully considered the industry bible ; and it was no coincidence that its birthplace was Antwerp. For over five centuries, Antwerp has been the epicenter of the global diamond industry, building up an unparalleled wealth of diamond heritage, improving the skills required to deliver the perfection that is summed up as “Cut in Antwerp”, mastering every aspect of the business. Contemporary diamond business remains characterized by a large amount of family businesses, with companies following in the footsteps of four, five, sometimes six generations of diamond professionals. But the world around us is evolving at a rapid pace, the strict boundaries between different industries are slowly fading, technology and digital strategies have become indispensable for any business.

In this increasingly globalized and digital world, the industry that was once exclusively available for those born and bred in the world of diamonds, is opening up ; new skills are required, new business models adopted, new technologies implemented. As we embrace these new developments and welcome others into this fascinating business, one thing remains constant. Today still, there is no such thing as a university degree in diamond manufacturing, no MBA in diamond trading. More than ever, “Hardness 10” will continue to prove its very relevance as the single most complete diamond encyclopedia, and I am sure that this life’s work, written by arguably one of the most knowledgeable diamond experts from Antwerp, will continue to do so for many years to come. Or as someone once said, “A classic is a book that has never finished saying what it has to say.”

I would like to commend Eddy Vleeschdrager for sharing his passion and knowledge with the reader in this unique and wonderful book.
Antwerp, June 2017

Stéphane Fischler
President Antwerp World Diamond Centre,
Vice-President of the World Diamond Council

Hardness 10, a must among diamond literature by G. Haazen

Diamond with a hardness of 10 ranks at the top of Mohs' scale of relative hardness of minerals. Malachite e.g. stands at 3.5 to 4, jade 6 to 6.5, emerald 7.5. «Durete 10» (Hardness 10) is the original title of a new book on diamonds, written by the Antwerp author E. Vleeschdrager and which has first been published by Gaston Lachurie in Paris.

Being president of the Union of Diamond Sawyers, manager of the SBD, the HRD (Diamond High Council) and the WTOCD, he is undoubtedly an authority on this complex matter.
There is no shortage of recent literature on diamonds, but the French speaking public was certainly not spoiled. « Durete 10» largely makes up for this arrears. It can be expected that this exhaustive work on the history, cutting of and trade in diamonds will very soon become one of the classics in its field.

Classic because it is an accurate working instrument for the dyed-in-the-wool diamond dealer, jeweller and even gemmologist and because it is readable and fascinating for a large public which is just interested in diamonds. Furthermore it is not just a book to adorn a well-filled library. In this book of 300 pages, the author discusses the characteristics of diamonds, including a few paragraphs on synthetic diamonds; the geology, prospection and mining; the major producing countries; the processing or polishing (cleaving, sawing, bruting, polishing, together some 1 50 pages. The equipment used by the diamond dealers.

The DTC is given pride of place in the chapter on trade and the importance of Antwerp as a world trade center stands out clearly. Also discussed are the standards established in recent years by the different world organisations for the evaluation of diamonds (the 4 C's) and of coloured stones as well as the most reliable certificates.

The book is completed with a few very practical attributes: a handy map on which the (approximate) weight of a diamond can be read according to the size of the polished stone; an extensive bibliography; an explanatory glossary and even a quadrilingual glossary: French, «Flemish», English, German. «Durete 10» contains only a few minor flaws. E.g. the Dutch translation of a number of terms from the diamond jargon should be corrected on language and printing mistakes in the next edition.

G. Haazen