Reviews Gems & Gemology, Summer 2017, Vol. 53, No. 2

Book Review: Ruby & Sapphire: A Gemologist’s Guide

Ruby & Sapphire: A Gemologist’s Guide
By Richard W. Hughes, with Wimon Manorotkul and E. Billie Hughes, hardcover, 816 pp., illus., publ. by RWH Publishing/Lotus Publishing, Bangkok, 2017, US$200.00.

Ruby & Sapphire: A Gemologist’s Guide is the updated version of the 1997 classic of this same name. This revised edition by Richard W. Hughes with coauthors Wimon Monorotkul and E. Billie Hughes offers exciting new features, including work by new contributors, updates within the text, and comprehensive analytical data. All the chapters have a beautiful new layout and are artistically designed with colored charts and diagrams, spectacular new photography, and extensive documentation. From the very first pages, Ruby & Sapphire transports the reader on a fantastic journey.

The book starts with a fascinating chapter reviewing the legends surrounding corundum throughout history. The reader will travel in this chapter from ancient civilizations through the Middle East and Europe of the Middle Ages and other eras. This chapter also introduces several antique jewels referenced in the “Ruby & Sapphire in the Ancient World” section written by Lisbet Thoresen.

The following chapters explore the sciences, beginning with the chemistry and crystallography of corundum in chapter 2. The trace-element chemistry of ruby and sapphire from different localities are detailed in a chart by contributor Kenneth Scarratt. Crystal forms, angles, twinning, shapes, and other habits are documented and described. Chapter 3 elaborates on the physics of corundum, including parting, fracture, hardness, and thermal properties. Electrical and optical properties of corundum are review together with phenomena such as color change, asterism, and chatoyancy of ruby and sapphire as well as trapiche stones.

Along with contributors John Emmett, Emily Dubinsky, and Kenneth Scarratt, Hughes defines the role of color in perception in chapter 4. “A Guide to Understanding Color” reviews the chromophores of natural corundum and their colors, using density color diagrams and absorption spectra to illustrate the concentration in ppma. It also analyzes the interactions of trace elements in corundum. This chapter also describes corundum’s visible absorption with the use of handheld spectroscopes. The different sections further explore the topics of absorption and transmission of light in corundum, with data collected by today’s modern spectrophotometers used for advanced gemology testing and research. Quantitative absorption spectra graphs and absorption coefficient formulae enrich this chapter as well.  IR spectra are introduced and detailed in “Seeing Infrared: Deconstructing the Infrared Spectra of Corundum” section by contributor Kenneth Scarratt. Paragraphs on luminescence and pleochroism conclude this chapter.

Hughes considers the next chapter, on the history of inclusion research and microscope illumination techniques as well as inclusion types and their formation “one of the most fascinating and rewarding aspects of gemology.” This chapter may be the most visually striking; it features photomicrographs from authors Richard Hughes and E. Billie Hughes as well as renowned gemologists John Koivula, Nathan Renfro, and Danny Sanchez. Iridescent features in Thai ruby, spectacular crystal inclusions in Mogok sapphire, exsolved rutile needles in Burmese ruby, and other scenes from the fascinating internal world of corundum are explored.

“Treatments” starts with the history of heat treatment in corundum, then moves into types of modern heat treatment (including diffusion treatments). Chapter 6 documents the treatment of several corundum varieties, including geuda sapphire, Mong Hsu ruby, Montana’s Rock Creek sapphire, with photographs before and after treatment. This chapter also describes how to detect treatment, with photomicrographs of altered inclusions, fissure filling, and other examples. Chapter 7 takes the reader into the world of synthetic corundum, including the different crystal growing processes, internal features, and gemological properties. This chapter also offers insight into advanced synthetic corundum growth techniques from Jennifer Stone-Sundberg.

With chapter 8, the book transitions into reviewing assembled materials and coated stones. Chapter 9 focuses on methods of fashioning, with splendid photographs and diagrams detailing cut orientation and shapes. Chapter 10 incorporates explains the qualities by which corundum is judged, including tone and saturation; clarity, cut and weight; phenomenon (when applicable); and quality ranking by locality. It also explores market trends and trade names, and judging phenomenon stones. The auction records of historic rubies and sapphires of note, such as the the 330 ct “Star of Asia,” are also detailed.

Chapter 11 elaborates on the material’s geological features, including rock types, corundum-bearing orogenic belts, and secondary deposits. This geology chapter prepares the reader for the following chapter on world sources. Chapter 12 features stunning photographs of landscapes and mines, rough and faceted specimens, and miners, as well as photomicrographs of ruby and sapphire that display the defining characteristics of different localities. Examples include the Kashmir “snowflake” and exsolved rutile silk in Mozambique ruby. Comprehensive maps and illustrations, timelines of ruby and sapphire discoveries in these countries, and photographs are included.

Since the first edition, a significant amount of information on African ruby and sapphire sources has been added. Gem corundum mines all over the continent are referenced, from southern Africa; southwestern Namibia; central and west African regions like Nigeria, Cameroon, Congo; to eastern countries mines in Uganda, Rwanda, Somalia, Malawi, and Tanzania. The largest sections covering African mines are devoted to Mozambique and Madagascar, which have been the sites of major corundum rushes since the first edition was published. Hughes offers exhaustive description and documentation of these localities. The Asian ruby and sapphire deposits have been also considerably documented and updated, particularly those in Myanmar (Burma), Thailand, Cambodia, and Sri Lanka.

The corundum localities along the Silk Road—Afghanistan, Tajikistan, Pakistan, Nepal, and China, for example—are explored, with their characteristics and properties thoroughly detailed and documented. In the American section, photography of Yogo Gulch sapphires from the William Larson collection, Rock Creek material, and Eldorado Bar Missouri River’s specimens show the beauty of corundum from Montana.

Finally Appendix A on Tagore’s Ruby & Sapphire are sections from the classic Mani-Mala (1879, 1881) by Tagore, featuring illustrations from the book. Appendix B concludes this wonderful book with prices and ID flow charts updated with new localities.

The book also features full-page advertisements from various gem trading companies between each chapter. Without these sponsors, such an amazing book could have not been printed, at least not at this incredibly affordable price point. This advertising also shows the trade industry vision and marketing approach at the time of publication; therefore, these serve as valuable references.

The impressive quantity of references, updates, and amount of information available in the new edition make Ruby & Sapphire an invaluable resource for people in the gem industry. But this book can captivate any reader, thanks to the fascinating crossroads between science, history, art, travel, and other fields.

Jonathan Muyal is a staff gemologist at GIA in Carlsbad, California.