Most rubies these days are glass filled and buyers should be informed about this process as it is in the best interests of the Gemstone Industry.
For the latest information on gemstone treatments, and to keep up with other important news breaking in the industry, follow the link below to the Gemstone Advisory Panel (GAP) section of Gem Rock Auctions forum frequently, to stay abreast of the goings on in the gemstone industry that are occurring at an ever increasing pace:
IMPORTANT INFORMATION FOR RUBY BUYERS
- see our Ruby comparison in pictures (Word document).
- See the Gemstone Advisory Panel Forum
FRANKENRUBIES AND YOU
By Alicia Taylor, ISG RG
Gemstone Advisory Panel Member
In a nutshell, until about 5 years ago the use of leaded glass was pretty much confined to being used for filling surface reaching fractures in diamonds. An Israeli diamond dealer named Yehuda pioneered the process in 1982, in order to make inferior diamonds usable and affordable to that segment of the market that couldn't otherwise afford them. This was a boon for industry sales, and there was nothing wrong with this treatment since Mr. Yehuda made full disclosure. Under observation, his treatment showed a nice blue or orange flash called the 'flash effect' that jewelers and gemologists could usually detect to identify the filled stones, so it became a perfectly acceptable and valuable treatment for diamonds in the trade for over 20 years, and is now also used to fill the holes left by laser drilling of interior inclusions, making them much harder to detect.
The process is basically the same as when glaziers repair cracks and dings in windshields, making them virtually disappear right before your eyes. This is because the filler is about the same density, and has a high refractive index, which causes light waves to travel uniformly through repaired fractures, rather than speeding up through the gap. Once filled, light travels at about the same speed through both the glass and the filler, causing the fracture to seemingly disappear, and become almost impossible to detect. It's the same premise when it's used on gems.
Jump forward to 2004, and suddenly leaded-glass filled rubies began appearing in the Thai gem market. The process involves heating the stones, then reheating them again packed in lead and silica-rich oxides, and reheating them over and over and over... under controlled conditions of temperature and pressure to keep them below corundum's melting point, until the desired results are obtained. The end result is a greatly enhanced ruby, whose color can also be improved with the addition of a coloring element to the mix, and since rubies are colored by chromium, a bit of chromium added to the mix can produce a fabulous looking ruby which, to the untrained eye, looks every bit as good as fine Burma ruby.
Fortunately, trained gemologists can usually (but not always) see the blue or orange 'flash effect' using darkfield illumination and their microscope, although sometimes it can be detected with just a loupe, and will frequently observe round air bubbles; a telltale sign of glass filling, with the bubbles captured in the glass.
But the treatment merely conceals a weak area in the stone, and leaded glass, not being nearly as hard as corundum, can easily be scratched during normal activities of everyday life, and the softer glass filler can easily be chipped right off the stone exposing the original fracture/fissure, so by no means can it be considered a permanent enhancement. The filler also naturally degrades over time, and must occasionally be polished, or even redone to maintain the stone's beauty, plus the stone must be removed to repair a setting, and all this has serious consequences on the value of the stone, making full and proper disclosure of paramount importance, if only because of the lengths that must be gone to to avoid damage to the filler while cleaning it, or when having to make repairs to the setting.
It was non-disclosure of this treatment, and not the treatment itself that nearly destroyed the ruby market when the Thai Frankenrubies began flooding the market without disclosure, since they could command the higher prices reserved for better quality natural untreated rubies until their deception was discovered, causing the ruby market to take a hit. But just as with Mr. Yehuda's diamond enhancement, there's a place in the market for these stones as long as they're sold with full disclosure.
But since then, not much has improved. As a matter of fact, at this point in time the ratio of glass to ruby has increased exponentially, to the point where many so-called 'rubies' on the market today contain more glass than ruby, and should probably be classified as 'composite', 'reconstituted', or even man-made stones since the glass is what's holding what little ruby is in them together. And that's exactly what you get when the filler is removed; crumbs of inferior ruby are all that's left, ...and yet they continue to change hands without disclosure, and sold as natural and untreated over 5 years later....
The extent of the problem was succinctly summed up by another ISG gemologist, whose comment about a particularly heavily treated ruby is all too true, and is quoted below, with permission:
"That one is so full of glass that if we had never heard of leaded glass filled ruby we may just pick up our loupe and then mistakenly inform the owner that it was just a piece of glass. The ruby would be easy to overlook by comparison."
That's how bad it's gotten! And if a stone improperly sold as natural and untreated begins to chip and deteriorate, the buyer will eventually be left with nothing but crumbs of inferior ruby, and will have legal recourse against the seller, who will be able to count themselves lucky if they're only sued for deceptive trade practices and fraud if they failed to use due diligence, and sold it without verifying exactly what it was, and supplying full and proper disclosure.
That's why wise and prudent sellers don't just accept what they're told as fact, and pass on whatever information has been given to them. They realize their reputations and their very livelihoods are at stake, and their success depends on their trustworthiness, which can be so easily damaged if they aren't vigilant and what they sell turns out to be other than what they said it was, and when it reaches that point, the burden of proof will be on the them to prove otherwise.
Both buyers and sellers need to be alert and aware of this, and remember:
Quality rubies are never sold for inferior ruby prices!
Only inferior rubies are; it's just plain common sense.
Yet when people find stones for sale that really look fantastic and are being sold as expensive, natural and untreated at unheard of prices, they lose all common sense to temptation and the rush of scoring a valuable gemstone for a song, if only for the euphoria of acquiring something expensive at a bargain basement price.
But more often than not it's done to resell the stone and turn a profit, which is so easily accomplished today with the internet at our fingertips that many just can't resist, and once purchased with the idea of turning a profit on the sale, the last thing anyone wants to do is have to sell it for less than they paid. But now more than ever, since it's a well-known fact that glass-filled rubies have flooded the market, as well as a myriad of other 'enhanced' gemstones, there's a real need to know exactly what you're selling because of the ramifications of not making full and proper disclosure.
So in case the treaters and merchants whose hands the gem passed through all the way up the ladder have been less than truthful, or simply parroted that it was natural and untreated based solely on the word of the last guy in the chain before them, you cannot just follow suit, and need to verify that it really is what you plan to list it as because the legal responsibility for making proper disclosure ultimately rests on the shoulders of the seller who profits from the sale to the consumer who lives where there are laws about proper disclosure and deceptive trade practices, which means you! And if you're a seller who uncovers the truth, you'll need proof your vendor gave you false information (whether through malice, or negligence), so use caution when buying directly from overseas sellers you know nothing about because it's hard enough to enforce laws locally, and if they live where disclosure laws are lax, unenforced, or worse, nonexistent, it's impossible and fruitless to even try.
Which is why it's always safer to buy from reputable dealers, which in turn means you always need to keep your ear to the ground for referrals to honest sellers known to trade in quality stones. And when you want to buy from dealers you've never heard of, it helps if they are trained gemologists, have tested the stone(s), and guarantee what they're selling.
But how many sellers actually bother to educate themselves, or are willing to invest the time it takes to stay informed on the latest findings, much less spend money on equipment? Sadly, not nearly as many as there needs to be, and the industry's image is being tarnished because of it.
And because selling gems as something they aren't has been going on for so long it's probably the second oldest profession, it's the consumer's responsibility to adhere to the adage;
"Let the buyer beware"....
To read more about glass field rubies, follow this link (note this is an external site).
Last Update: 23 Jul