Description of the author’s eye-witness visit to Vietnam’s Quy Chau ruby mines.

corundum, Vietnam.12, gems

corundum, ruby, synthetic corundum.7, assembled stones.8, gems

Discussion of the appearance in Thailand of large quantities of ruby from northern Vietnam.

ruby, Vietnam.12, Burma.12, Thailand.12, corundum, gems

ruby, Vietnam.12, corundum, gems

History of ruby and sapphire in Thailand, Laos and Cambodia.

corundum, ruby, sapphire, Thailand.12, Cambodia.12, Laos.11, methods of fashioning.8, quality.9, gems

Pssst. pssst. Want a hot tip? Hit the library and dredge up a gem treatment, preferably one developed years ago, so that most have forgotten it. Spice it up a bit, give it a jazzier name. Then throw a piece into a parcel of naturals and take it round to a lab on… say… New Year's Eve. Did the lab muff the identification? Great! Call in the trade media to roll out the product (and don't forget to show them the natural report). Now promote the bejesus out of it by telling people that it's virtually unidentifiable.Sound crazy? It shouldn't. It should sound familiar, like deep surface diffusion. Most in the gem trade have now heard of the deep surface diffusion-treated sapphires. But few know how to spot them. And fewer still realize that surface diffusion is nothing new. But good treatments are a bit like vampires. No matter how often you kill them they always come back to haunt you.

corundum, sapphire, diffusion treatments.6, gems

Discussion of the appearance in Thailand of large quantities of ruby from northern Vietnam.

corundum, ruby, Vietnam.12, inclusions.5, gems

Review of events in the Bangkok gem market, including the appearance of large quantities of ruby from northern Vietnam.

corundum, ruby, Vietnam.12, inclusions.5, gems

Ruby & Sapphire explores the fascinating story of the corundum family of gems. This single volume reporesents a slightly updated version of “Corundum,” the first detailed examination of both ruby and the various sapphires, widely considered to be the most sought after of all gems. The author draws on his many years of experience to take the reader back in time to the various Asian kingdoms that were the primary sources of the fabled ruby and sapphire. For those interested in rubies and sapphires, this book offers an unparallelled look at the world's premier gems.

corundum, ruby, sapphire, gems, gems

gem treatment, heat treatments.6, corundum, ruby, sapphire, gems

Although not exactly new to gemology, surface diffusion-treated corundums (SDTCs) have recently been creating quite a stir in world gem markets, particularly the important Bangkok corundum market. The following article examines the subject in detail, starting with the original Linde patents and continuing up to the present-day Deep Diffusion" treatment. Methods of identification are discussed, as well as much of the back-room politics and maneuvering which has surrounded this controversial treated gem material. Also included is a quick reference table giving a detailed summary of the key identifying features of all types of natural, treated and synthetic corundums."

surface diffusion treatments.6, blue sapphire, corundum, gems, lattice diffusion

Sales of diamonds account for a large percentage of a typical jeweler's gemstone business. One of the important reasons for the dominance of diamond in the gem market is the existence of a comprehensive and internationally accepted system of quality analysis. Thls allows laypeople to buy with confidence as, with a diamond grading report, they have an independent, expert" opinion of the stone’s quality. But is this "expert" opinion, itself, always infallible, and do the different quality "steps" really indicate genuine differences in quality? Despite what some may think.the answers to these questions will have a definite impact on the colored stone business, as the trade is now moving towards the adoption of a similar system for the grading of colored stones. It is with this in mind that we examine some of the problems that the trade now encounters with the present diamond grading system."

corundum, quality.9, diamond grading, gems

A summary of corundum identification.

gems, gem identification, corundum gem identification

By this time, most readers will have read all about what went down at the ICA Congress in Colombo, Sri Lanka last May. So we will just make a few brief comments on what we liked and didn't like.

corundum, pink sapphire, nomenclature, gems

Rubies and sapphires are widely considered to be among the most sought after and precious of gems. Together they account for over fifty percent of the world trade in colored gemstones. This book is the first from Richard Hughes on the subject, and the first major work to be devoted entirely to the corundum family of gemstones. It covers all aspects of rubies and sapphires, beginning with their history, chemical and physical properties. Other chapters look at treatments, synthetic corundums, methods of fashioning, famous rubies and sapphires, formation of corundum deposits and world sources, providing a valuable reference source for jewelers, gemologists, students, and the general reader.

corundum, gems

No gemologist today would deny the importance of inclusions to the study of gemology. They are vital tools in separating synthetic gems from natural, and their importance will certainly increase along with the growing sophistication of treated gems. However, the question of inclusion-based country-of-origin reports does not find all gemologists and traders in agreement. Some support the practice; others do not. The following article takes a close look at the entire question of lab-issued origin reports, asking… a. are origin reports accurate within a reasonable degree of error using the current methods? b. even if origin reports are reasonably accurate, how are they being used in today's market? Do they provide useful collector information and protection to prospective customers, or are they merely a diversion for drawing the buyer's attention away from the stone's overall appearance and quality, to some ill-definable factor, such as origin? c. are origin reports akin to the authentication of a painting by a master artist, or do natural gems have only one artist Mother Nature? The purpose of this article is, thus, to explore objectively the arguments for and against lab origin reports. First the author explains why he believes origin reports are not totally reliable and definitely not in the best interests of the consumer. Supporters are then given the opportunity for rebuttal, explaining why they think Mr. Hughes has lost his mind. It is our hope that, out of the fray, readers, defenders of the faith, and opponents will better understand this question of origin.

corundum, India.12, Kashmir.11, Burma.12, gems

Review of happenings in the Bangkok gem market.

corundum, quality.10, Laos.12, gems

A brief inclusion study was done on a small sampling of Turkana sapphires provided by Ted Themelis. Perhaps the most distinctive feature throughout the lot of approximately 30 pieces was a slight cloudiness, or girasol," if you will. While in reflected light the stone might appear blue or green, in transmitted light an oily yellowish "diesel" appearance was seen (see Figure 1). This was found in virtually all specimens, except the one piece which had been heat treated. Heat treatment removed this cloudiness, as well as improving the color, suggesting that the cloudiness may be exsolved Ti and/or Fe compounds."

corundum, sapphire, East Africa, Kenya.12, inclusions.5, gems

News from the Bangkok gem market.

corundum, quality.9, gems

News from the Bangkok gem market, including the opening of the huge S.A.P. sapphire mine at Bo Ploi, Kanchanaburi.

Thailand.12, Bo Ploi, gems