This article provides a chronological timeline for the controversy surrounding treated andesine feldspar. In addition, common questions regarding the controversy are addressed. An extensive bibliography is provided at the end.

gems, andesine, feldspar, Tibet, China

The history of the Lao sapphire mines at Ban Huay Xai is detailed, along with modern mining by Hong Kong based Sino Resources Mining Corp. Ltd. from 2006–2012.

Corundum, Laos.12, Huay Xai, gems

Since the late 1960's, East Africa has been home to some of planet earth's greatest gem discoveries. And yet, little has been written about certain of these finds. In the autumn of 2007, the authors set out to fill in the gaps, specifically regarding Tanzania's Mahenge, Songea and Tunduru regions.

corundum, Tanzania.12, gems

The Thai city of Chanthaburi (จันทบุรี) may be small, but it has played an important role in both the history of Thailand and the history of the gem trade. Taking its name from the Thai word for moon ('chan'), this petite town is among the most charming in the Land of Smiles. Richard W. Hughes takes a look at Thailand's No. 1 gem town.

corundum, Thailand.12, Cambodia.12, gems

Traditional gemology considers itself a science, but typically omits a key element of the scientific method. And is gemology simply a science, or something more? Read on to learn the answer…

gems, gem nomenclature, corundum, heat treatment, Broken Bangle

The subject of andesine in Tibet has been one of controversy since 2008. This article examines the history of the controversy, along with detailing an October 2010 visit to the Tibetan andesine mines.

andesine, Congo, Tibet, China, Oregon, sunstone, gems

A celebration of the spinel gems and the lands from which they come.

spinel, Burma, Tanzania, Vietnam, Sri Lanka, Madagascar, corundum, Quality.10, gems

Corundum has been known in Mozambique since the Portuguese colonial times (Afonso, R.S., Marques, J.M. , 1998, Lächelt, S., 2004) but very little information has been published about rubies or sapphires from Mozambique in the gemological literature as the production was so small and most of the stones produced were cabochon quality at best. Nevertheless, the gem markets in Bangkok and other places have recently started to see an increase in rubies coming out of Mozambique. Most of the stones seen were heavily fractured and mainly used as a base material for lead glass treatment, but some stones seen at the GIA Laboratories in Bangkok, New York and Carlsbad were fine enough to be faceted and used in jewelry without any treatment. A preliminary study on rubies reportedly from the Niassa province was released by GIA gemologists on March 22nd 2009 (Pardieu, V.P., Thanachakaphad, J. , 2009). After some inquiries it soon became apparent that there were several sources and a GIA Field Expedition to the various ruby mining areas of Northern Mozambique took place and is still ongoing at the end of 2009. Rubies and sapphires in Northern Mozambique have been mined from 4 different deposits, 3 of them located in the Niassa province and one in the Cabo Delgado province, over recent years.

corundum, geology.11, Mozambique.12, gems

One may be the lonliest number, but thirteen is something else again. In most buildings, 13 is so cursed they skip that floor and, perhaps not coincidentally, childhood dies at that age. Roll the dice and you never hit 13. It's a fact. Thirteen years ago I set out with my wife and young daughter to find Thailand's last remaining ruby mine

corundum, Thailand.12, Cambodia.12, gems

Spinel is rising. Like a phoenix, a gem that for centuries was associated with power, fire, beauty and life, is back again. Over the past several years, interest in spinel has grown and I am delighted to see the newfound fame for classic gem. I first became interested in gemology while studying the history of the 100 Years’ War between France and England. Who could forget the Black Prince’s Ruby, a stone given by the Spanish king to the Black Prince of England as payment for his military support in the civil war of 1366. Later, in 1415, the stone was said to have saved the life of King Henry V of England at the battle of Agincourt. Henry, who had placed the large red orb on his helmet, was struck by the battle axe of the French Duke of Alencon. Sword hit stone; both the ruby and Henry survived. If these stories were not already amazing enough, imagine a costly military campaign paid for entirely with a single gemstone. These are the legends of the Black Prince’s Ruby. But my greatest astonishment was learning that that the gem was not a ruby at all but, in fact, a red spinel. Since I had no idea what a spinel was, I decided to learn more about this mysterious gem. Thus began my interest in gemology. The gemology of spinel is a pleasure. Unlike ruby, there are few treatments and separation from both synthetics and simulants is straightforward. Nevertheless spinel is a rich subject, with a history nearly as long as ruby itself. The past fame, disgrace and recent resurrection of the gem are a lesson in the importance of nomenclature in marketing. Since gemology is truly a human science—mixing science, history, geography, art, trade and terminology—we must understand that human emotion is a crucial factor in marketing. Gems, even if rare and beautiful, also need a good name, and spinel is a classic example of that fact.

spinel, Burma, Tanzania, Vietnam, Sri Lanka, Madagascar, gems

Most gemologists are familiar with the direct vision spectroscope. This instrument uses a series of prisms or a diffraction grating to separate white light into its spectral components. If white light is passed through a gem, it will reveal any areas of absorption or emission. The main limitation of the direct vision spectroscope is that it can only analyze the visible region (400–700 nm), but a small portion of the electromagnetic spectrum.

corundum, color.4, gems

This article discusses the use of beryllium to treat blue sapphires.

corundum, treatments.6, gems

It is evening in the Madagascan town of Andilamena. In a small restaurant, three Hogmies and one Malagasy pore over a map, intensely focused on a blank spot where no road goes, miles from the nearest settlement. The Hogmies have traveled halfway around the world to visit this miniscule cartographic smudge of tightly wound contour lines. For it is here that Madagascar’s finest sapphires are said to be found. But perhaps I am getting ahead of myself. Let me begin a bit further back... My first recollection of Madagascar was grade school, where we dutifully learned that a prehistoric fish, long thought extinct, had been fished from the coastal waters of this errant isle. Later, in gemology class, my teacher again brought up the subject of this forgotten land, mentioning that the famous French naturalist, Alfred Lacroix had written a paper about it (Un Voyage au Pays des Béryls). From that moment on, Madagascar became known to me not just as something out of a Jules Verne novel, but as the “Beryl Island.” The Island of Madagascar is an anomaly in many respects. While lying just 400 km from the coast of Africa, it was not settled until roughly 2000 years ago, and not by Africans, but by adventurous sailors from the Malayo-Indonesian Archipelago, some 6400 km to the east. Today the country’s human population is a tumultuous stew spiced with Malay, African, Arab, French, Chinese and Indian ingredients.

corundum, geology.11, Madagascar.12, gems

In our business, travel should be de rigueur. But the headlines frighten so many away. Boo! Earth is one giant pool of war, disease and pestilence. Boo! International travel is undertaken only by the clinically insane or those with Special Ops experience. Boo! If the pox or pollution don't gettcha, al Qaeda is close behind. As Lou Reed sang: You've got a black .38 and a gravity knife. You still have to ride the train." Lou was singing about the New York subways. Having braved Manhattan's dangerous tunnels, we feel qualified to discuss what some might regard as an even greater peril: travel to Tajikistan. This article is based on a 2006 expedition to Tajikistan’s famous Kuh-i-Lal (spinel) and Snyzne (ruby) mines."

corundum, Afghanistan.12, China.12, Tajikistan.12, spinel, gems

A gemologist’s life would be far easier if gems were cut as parallel-sided plates. But they’re not. Facets are designed to reflect light back to the viewer, not transmit it. This means light entering the gemstone from behind (transmitted light) will typically not pass straight through. If we want to see inclusions, we must constantly change the light paths through the gemstone. This is done by changing the position of the gemstone relative to the light and changing the light relative to the gem. The most versatile and controllable method of doing this is with the fiber-optic light, an illumination technique “darker” than even darkfield. During a recent routine identification of a natural chrysoberyl a startling difference in two distinctly different types of illumination commonly used in the examination of gemstones was clearly revealed. These two methods are darkfield and fiber-optic illumination. When this chrysoberyl was studied in darkfield (Figure 1), only a fine linear growth band was seen. However, when fiber-optic lighting was directed in along the girdle plane, bundles of fine light-scattering silky needles extending at 90˚ from the linear growth band became abundantly clear. At the same time the linear growth band itself was also more clearly detailed (Figure 2). The difference in the amount of visual information provided by these two different lighting techniques was startling. In this instance darkfield was clearly inferior to fiber-optic illumination.

corundum, inclusions.5, photomicrography, gems

While a passport typically conjures up images of freedom, the open road and travel to exotic locales, not every destination is five-star. This point was driven home during the examination of a group of yellow sapphires recently sent to the laboratory for identification.

corundum, treatments.6, gems

Virtually all gemologists are aware of the curved growth lines and gas bubbles in Verneuil (flame-fusion) synthetic corundum, but few understand exactly why they occur and how they are distributed in these stones. This article clarifies these important identifying features.

corundum, synthetic corundum.7, gems

What follows is a love story. We admit it. Our heart is on our sleeves. We are smitten, head-over-heels in love with the exotic and beguiling internal lattice that gemologists call silk." How do we love thee? Let us count the ways. You are the one that lets some of our rubies and sapphires sparkle like the night sky, your asterism such a wonder of nature. Not to mention your beauty as you wink up at us when the light is just so. And finally, you are our guardian, our coalmine canary, a tiny thermometer in our gems, willing to sacrifice your own life to let us know when Man’s ego has grown so large that he thinks he can play God. For this alone, we sing your praises."

corundum, inclusions.5, gems

One of the greatest gemological challenges is determining if a ruby or sapphire has been heat treated. UV fluorescence can assist in that identification, as well as detecting fillers in emerald.

corundum, color.4, treatments.6, gems

A discussion of how inclusion patterns mimic crystallographic symmetry in ruby and sapphire.

corundum, inclusions.5, gems