Leaded Glass Filled Ruby

A good number of years ago I walked unsuspectingly into the gem market area of Chanthaburi Thailand and saw people with piles and piles of large rubies everywhere. What were these new and plentiful gems? Many had little color for ruby and had a ghostly appearance I had never seen in a gem before. Others were top color and the prices were huge when it seemed they had just swept up after a storm of them. I did not buy any as they were far too suspect but I did meet up with a gemologist friend later that had also just witnessed the same curiosity. "Leaded glass filled" he said, "and not the kind of glass we see in flux healed rubies either"
As it turns out there were tons of ruby material in Africa that had so many fissures and cracks in it that it was basically worthless. The experienced gem treaters of Chanthaburi Thailand figured out that they could heat the severely cracked ruby with leaded glass and it was basically undetectable with gemological instruments such as refractometers, spectrometers, specific gravity readings and more. It created a somewhat marketable material especially until consumers get fed up with it and the price falls below where it is worth treating, which is a likely future event. But for now and for a good number of years yet to come, you will see beautiful glass filled rubies in places where they should not be such as in fine jewelry stores with no disclosure as to the exact nature of the enhancement. Others will and have already made it into a jewelers pickle which renders them back to a very ugly condition as the acid eats the glass.
How can we proctect ourselves from buying these short-lived beauties when we think we are buying quality rubies that will last many lifetimes? For starters, a 10x loupe can help a great deal. Often there will be bubbles in glass and that will be a huge red flag about this treatment. Not all will show bubbles with a loupe so it is not conclusive proof for no treatment, of course. Another tell tale observation with the loupe will be blue flashes. Turn the stone while looking at it with your loupe. Some leaded glass filled will show this color, natural untreated will not. One final characteristic will be slight variations in the sheen of the table, sort of like tiny wavy lines of a slightly different degree of reflection, rivers of glass. Beyond that you will need a microscope, a friend with a microscope, or a lab you can trust. The treaters know how we detect these frauds and are working to eliminate the bubbles and the blue flashes and the rivers of glass in order to create a more 'marketable' product. Buyer beware.

Flux and More Flux

Shortly after I had the flux healed ruby information under my belt I was wandering around a gemstone market and saw a very lovely ruby in a case. It was about 3 carat and a very glowing red. I asked to see it and the lady brought it out and I immediately put my 10x loupe to it. I was stunned. Inside this very red stone was very translucent clarity and well defined flux like patterns. There also appeared to be a few comforting black spots. I say comforting because we all know synthetics will be perfectly clean, no black spots and no flux fingerprints, right?
Well, I asked her calmly what the price was and she looked me straight in the eye and with a twinkle told me $500 USD. Holy cow, over a hundred a carat in this location. If this was the real McCoy it was worth way more than that but $500 is a ton of money here soooo....
I told her the price was a little high but did she have any more. Her eyes lit up again and she removed a piece of parcel paper from inside to case and unfolded it. Inside were about 100 pieces, all absolutely gorgeous. Some quick math and a quick glance at the old rubber slippers she was wearing told me I had some room to negotiate. When she wouldn't accept my much lower offer I noticed another vendor, 2 booths down getting very anxious to catch my eye. I politely made my departure for the next lady and was intercepted by a man that insisted on a word in private. He told me I was about to be scammed and he could show me where to buy the rubies that I really wanted. Off we went on foot to a small jewelry shop. Much higher scale, well dressed employees and a clean shop. He explained in Burmese what I wanted and out came the rubies. The exact same look but with an even higher price. They even demonstrated with some 'test' to prove that theirs was real and how those others must be some kind of plastic or something. Suddenly I noticed the clock and exclaimed in a lie that I was to meet my girlfriend in 5 minutes and had to run. Run I did, circling back to the ladies with the rubies.
I found the second one that had been trying to lure me over. She had the same merchandise and accepted an even lower offer than the first lady had refused. Now I had about 300 carats of something. The original lady made her way over to watch the transaction and said she would now accept my original offer. Of course I said that the offer was now lower, a little lower than what I had just paid, in fact. She accepted it with a smile after a little pleading and now I had well over 500 carats of something I knew was interesting.
I needed a second opinion or more so I took some to my local lapidary club. The president was baffled and took one to show an 'expert' he would see next month. Several months passed and she was still checking on it. I didn't want to wait longer but wanted to sell them. I had a regular route where I set up a booth in various markets so I labeled them as synthetic and put them out there. Every gem lover always noticed them and had me pull them out. I enjoyed watching them as they noticed the inclusions. Several experts took me under their wing and told me that these were not synthetics and my price of $25 a carat was ridiculously low. I insisted that I was OK with that price and they were then delighted to relieve me of some. I traveled around to various jewelers and had many adventures with them trying to figure these things out. Definitely ruby but I was seeing inclusions in the microscope that I still have not seen again to this day. After several more months and half of them sold, one jeweler knew of a lab I could mail them to. He had to know as he wanted to buy all the rest if they checked out as natural as he thought they must be.
Into the scene steps Bear Williams of Stone Group Labs. After receiving the package, Bear called me and wanted to know where I had gotten these as they were highly unusual. The surprising diagnostic was a flame fusion ruby that perhaps had been heated then cooled quickly causing it to crack, perhaps then it had been reheated with Borax flux to heal the cracks. This type of ruby had not yet been documented as far as he knew. A little more than a year later there was an alert from a major gem lab that this type of stone had been observed. Now, quite a number of years later, many experts are still selling these as naturals at well over $100 per carat. I now sell them for $5 a carat retail in my eBay store. They do make an excellent study stone, are very cool just to look at and show and also make a very stunning piece of jewelry.

Flux Healed Hmong Shu Ruby

Pictured above is a flux healed ruby crystal from Mong Shu Burma, cabochon grade. Notice the 'candy coating' of melted Borax.

When I first started looking into gemology and the gemstone industry I couldn't help but notice the topic of Flux Treated Rubies. It was being treated as a new topic however, it may have been going on for several years by then.
What does this term, flux treated, mean? First off, flux is an additive used to help melt a substance at a lower temp than it would without it. We use flux when we solder plumbing pipes or weld steel. In silver and goldsmithing I use flux to help melt my alloys as well as to solder my pieces. The flux I use is simple Borax, not surprisingly, the flux used to treat rubies is often the same.
Coincidentally I built a home 45 minutes from the border of Burma where the rough Ruby material used in flux heated rubies was entering Thailand. The rough was from an area called Mong Shu. It was bluish/purple and badly cracked. Most of it had been unsellable thus far.
Borax had been found to reduce the thermal shock of heating stones, in other words, if you would sprinkle some of this white powder onto your rough stones before you heated them you would have less broken and cracked stones. This knowledge lead to a miraculous discovery. When you added Borax to your severely fractured Mong Shu rough and heated it to near melting point, your rough was no longer fractured!! Plus the blue/purple color had change to a beautiful ruby red!!
Now this was huge, not only because Mong Shu had lots of this rough but because little fine ruby had been found anywhere for a long time. Ruby with great color and no feathers/cracks was very rare.
How did it have no cracks? The flux melted, like it always does, and ran down into the cracks. Here it caused the ruby material on each side of the crack to melt and stick together, very similar to welding/soldering. Now the cracks were 'healed' turning a material from being fragile to being even more durable than a common ruby as they often have some feathers/weak points.
So then the labs had to come up with terms for this in their reports and in my opinion did a poor job of communicating. Some like to call this ruby that melted and welded together, 'synthetic ruby'. That may be scientifically accurate but is misleading to most people as it sounds like a man made ruby was added when it was not. Any natural ruby that has melted can be defined as a synthetic ruby. Others said there was a 'glass filling in the cracks' which is also misleading in my opinion as most of us would understand that to mean the cracks were still there but were now filled with the same thing we make windows out of. Later somebody said 'flux healed' and that seems much more easy to understand.
For years dealers complained about the process as it was certainly more than simple heat treatment but they could not stop the industry from accepting it. The truth was, they were beautiful, durable and still rare. Those are the three things that make a gemstone a 'gem'.
Now I see that the worlds most sought after Ruby rough, Burmese Mogok, is also heated with Borax. The price only seems to be affected at the very top end nowadays. One dealer friend here in Thailand was trying to buy a 2.5 carat ruby from another for $15,000 US dollars but the owner said he was giong to hold out for $25,000. I asked whether or not it was unheated Mogok, the answer was no, flux healed Mong Shu.