Fracture Healing / Filling of Möng Hsu ruby

Foreign affairs - A well-known European dealer sells a 2.5-carat Möng Hsu ruby to a major jeweler in Europe. This jeweler then sells the stone to a Japanese client through their Japanese subsidiary. The client now takes the stone to a gemological lab, which issues a report stating that the gem's fractures are filled with a foreign substance. Now the fun really starts.

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By Richard W. HughesMore from this author

PICTURE THIS: a well-known European dealer sells a 2.5-carat Möng Hsu ruby to a major jeweler in Europe. This jeweler then sells the stone to a Japanese client through their Japanese subsidiary. The client now takes the stone to a gemological lab, which issues a report stating that the gem's fractures are filled with a foreign substance.

Now the fun really starts. Feeling cheated, the customer returns the stone and demands a full refund. Thus begins a lawsuit which involves several firms, spans two continents and is still snaking its way through the court system in France.

Fracture healing/filling of Möng Hsu ruby - Foreign affairs 1.jpg - 16.09 K

Today, courts are increasingly being called upon to arbitrate such disputes, largely because sellers have failed to disclose the glass infilling/healing of fractures in Möng Hsu ruby from Burma. The problem is a huge one, a corundum conundrum that will only escalate until the trade begins to enforce a policy of full disclosure of all gemstone enhancements. The following article examines the roots of the issue.

Möng Hsu is not Mogok

In terms of quality, Möng Hsu rubies cannot compete with Mogok stones. There are two major problems. The first is a strong purplish color, making most stones look like poor rhodolite garnet. Ordinary heat treatment eliminates the purplish tint, and the market generally accepts such heated stones without a quibble.

This is not the case for the second problem. Most Möng Hsu stones are heavily fractured and Thai burners have combated the cracking by filling the cracks with glass. Heating the stones with borax and other chemicals actually melts their surfaces, including the surfaces of cracks. This molten material then solidifies into a glass, filling and healing the fractures shut. In the broadest sense, this is akin to the oiling of emerald-both treatments involve filling fractures with a transparent, colorless substance. Similar to placing an ice cube in water, a filled fracture is much less visible because the filler replaces air (RI = 1.00) with a substance which has an RI that more closely matches the gem itself (1.76-1.77).

However, the glass infilling of Möng Hsu rubies differs in two important respects:

  1. The Möng Hsu ruby treatment is permanent-unlike the oil in an oiled emerald, the glass will not drain out in the future.
    2. The Möng Hsu ruby treatment actually improves a stone's durability, since the fractures are bonded together with glass.

Hence we have a superior treatment for Möng Hsu ruby, one which is actually more stable than ordinary oiling. So what is all the fuss about? First, purchasers of ruby are not accustomed to buying heavily-fractured stones. Unlike emerald, clean rubies do exist. Second, the glass infilling can impact the weight of the stone.

But the biggest problem was something quite simple-when Thai burners starting glass infilling, they did not tell their customers. Customers believed they were buying stones for which only ordinary heat had been applied. When they learned otherwise, they rejected the goods. To most dealers and jewelers, fracture filling/healing with a foreign substance such as glass represents open-heart surgery, not just a haircut. Whether we like it or not, many dealers, jewelers and retail buyers of precious stones do not want to buy stones which have been radically altered in such a way.

The idea of fracture filling/healing with glass turns them off. Unfortunately, monkeying with stones and not telling the buyer has been business-as-usual in Thailand for years. It started with ordinary heating of corundums (mid-1970s), passed on to glass-filling of surface pits in ruby (1984), surface diffusion of blue sapphire (1988) and now glass fracture-healing/filling (1992). Market acceptance of ordinary heating was de facto; with no gem lab in Bangkok in the mid-1970s to warn them, when foreign buyers found out about this difficult-to-identify enhancement, they had an inventory full of heated gems. This was not the case with the other enhancements. A gem-testing lab was founded in Bangkok in 1978. When the glass pit-filling and surface diffusion first appeared in Thailand, they were quickly recognized by local gemologists and rejected by the market as a whole.

But the fracture-healing/filling of Möng Hsu rubies was initially passed over by local gemologists, in part because it is difficult to detect and in part because, frankly, certain Bangkok gemologists became overly influenced by traders. Even when they did detect the enhancement, they downplayed its significance, going so far as to declare that it would not be mentioned on identification reports if it wasn't visible under greater than 10¥ magnification. Foreign gemologists and dealers were not so kind. Many rejected such filled goods outright, particularly in the important Japanese market.

This has created a very real problem, where the enhancement is generally accepted by Bangkok dealers/gemologists, but rejected by those outside the country. The result is that goods are returned amidst much name-calling and hand-wringing, a situation from which only lawyers will benefit. Compounding the problem is the fact that laboratories around the world do not have uniform methods of describing or dealing with this enhancement. Some cannot even properly identify it or distinguish between naturally-occurring inclusions and the glass infilling.

Desperately Seeking Solutions

So, what to do? First, gem trade must get together on this question and decide on a solution to the mess. Today's world is one market, not one-hundred markets. This global trade makes it important that the solutions to this problem be a global one, not local.

For starters, Thailand's gem traders and treaters need to acknowledge that a mistake was made in not declaring this treatment from the outset. In the strictest sense, the problem is one of the Thai gem trade's own making. Had they been honest in properly labeling their goods from the start, they would not find themselves in this position.

On the other hand, foreign buyers need to acknowledge that some sort of enhancement is needed for Möng Hsu ruby. As anyone who as ever viewed the untreated stone can testify, the Möng Hsu ruby is not a viable gem without enhancement. The enhancement results in a material which is both beautiful and stable. There is certainly nothing wrong with that, so long as it is properly described.

Overall, we all must stop kidding ourselves. We must realize that, in the eyes of the retail gem customer, the high-temperature heating and glass impregnation of a ruby is not the same as simply cutting and polishing it. No amount of explaining will make it so. A gem which only requires polishing to reveal its beauty is far rarer than something which needs both polishing and ordinary heating. And that is rarer than something like the Möng Hsu ruby, which needs polishing, high-temperature heating, fracture healing and glass impregnation. The market should reflect these realities in its descriptions of goods and, most importantly, in its pricing. Remember, gems and jewelry are luxuries. They compete against a number of different goods and services. If we don't start getting our act together, that retail customer will stop buying more than just rubies.


Solutions rarely come easily. But the first step to solving any problem is to discuss it. The authors believe it is far better to discuss problems without solving them that to solve problems without discussion. We are interested in the views and ideas of others.

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Richard W. Hughes

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