The Story of Ruby

For many years, rubies have been considered the king of colored gemstones. If rubies had a benefactor like DeBeers rooting for them, rubies would have without a doubt been the most valuable and most in-demand gemstone. Unfortunately, diamonds had DeBeers as their cheerleader, so rubies have taken a back seat to their richer gemstone brother for decades. Indeed, If you consider the beautiful color of ruby and the fact that it is far more rare than a diamond, rubies should be at the top of the “Precious Gemstones” list. Today, however, we will put all of this aside and simply look at how to identify rubies including the treated and created types.

The identification of ruby is fairly easy even for the most basically trained gemologist. If you have a red gemstone with refractive indices in the 1.76 to 1.77 range, (which makes it double refractive), a specific gravity of 4.00, and a unique spectroscope spectrum, you are going to have a corundum, ruby. There is nothing else out there that could possibly fit that set of gemological test results. The real challenge comes with trying to identify if a ruby has been treated or is lab created. That will be our purpose today as we tell The Story of Ruby.

Two Types of Ruby Treatment

We need to first establish that gemstone treatments are good. Without the treatment of lesser quality gemstones to improve their beauty we would have to rely only on the very top quality of gemstone crystals coming out of the mines. In short, we would not have enough product to meet the demand of the market. And of course, any market that cannot supply the demand for the product eventually fails. So, when we talk about the treatment of rubies, we need to remember that without these treatments rubies will be far more expensive and far more difficult to obtain.

Flux Enhanced Rubies

In this process, a flux material is forced into surface breaking fissures in a ruby crystal. The ruby is then heated to a very high temperature and the flux material serves as a regrowth medium to cause the fissure to be “healed,” or filled in with newly created material in the fissures. (Themelis 2004) While this process tends to leave residual flux in these fissures, which can often be verified through low power magnification, it also leaves the ruby far more stable. The fissures are now filled with new growth rather than simply filled with leaded glass, which is the other process.

Glass Filled Rubies

This process is very much the same as fracture-filled diamonds, or to repair an impact chip on an automobile windshield. What is usually a leaded glass material of the same refractive index as the material being filled is introduced into surface breaking fissures. Since the glass is of the same refractive index as the material it is filling, the light passes through without being altered by the filler material. As a result, these filled fractures are much more difficult to see. Which is both good and bad. It is good because it makes these surface reaching fissures virtually disappear in rubies and make them far more beautiful. But it can be bad when a goldsmith is working on a ring and fails to either remove the stone or does not heat-sink the stone, then applies a torch to the ring and the heat expansion causes the ruby to break…sometimes catastrophically.

There are obviously more treatments that can be done to Ruby, particularly with heat treatment. But for our purpose today, these two types are what we wanted to review.

Identifying Lab Created Rubies

The identification of lab created rubies will range from fairly simple to extremely difficult. For that reason, we cannot possibly cover the entire topic in this article. However, below are some specific things you can look for to give you indicators that will be of service in making the identification of a lab created ruby. Unless otherwise indicated, these are all indicators and not diagnostic. Please keep that in mind.

Fluorescence as an Indicator

Regardless of the growth type, most lab created rubies will react very strongly to long wave ultra-violet light. This is due to the absence of iron. Iron in a gemstone tends to subdue colors by absorbing energy. Natural rubies very often have natural iron which causes the fluorescent reaction to be subdued. In order to maximize the brilliance of the red color, lab grown rubies are absent of iron which, in turn, allows for a bright reaction to UV. However, this issue does not always apply as mined rubies from certain locations are naturally low in iron. Despite this caveat, for someone well versed in viewing natural v. created rubies under a UV light, the separation of earth-mined rubies and lab created rubies can be fairly easy as seen below.

Flame Fusion Rubies

Rubies created by the flame fusion method will be fairly easy to identify under a microscope. The curved shape of flame fusion formation leaves a tell-tale structure of striations that are diagnostic when the ruby is also void of inclusions and has a very strong reaction to long wave fluorescence. Flame fusion rubies are plentiful and very affordable on the market.

Flux Melt Rubies

Creating rubies with the flux melt method produces a far more natural looking ruby, and a much more expensive ruby. The fingerprint-type inclusions in a flux melt ruby can very closely mimic those seen in both treated ruby and earth-mined ruby. This requires a gemologist to have a lot of experience examining all types of rubies in order to understand and identify the flux melt inclusions. There are two strong indicators that can be used to help in the decision. The first is that the flux melt rubies will be highly reactive to ultraviolet fluorescence due  to a lack of iron in the crystal. The second is that most lab growers will put a lot of chromium in their lab grown rubies in order to produce the brightest red color. The result is a very strong reaction to the chromium lines in the spectroscope. Once again, these are strong indicators, but they are not diagnostic of a specifically flux melt Ruby.

Star Rubies

You should also be very careful about star rubies that are being offered at very low prices. There is a process by which flame fusion rubies are surface treated to create artificial stars on the gemstones. While these are fairly easy to identify for a trained gemologist, they can be quite confusing to the untrained and to consumers.

Bogus Lab Reports

One of the biggest problems facing the industry is bogus lab reports. Since there are no industry standards and no oversight of the gemological labs it is very easy for an unscrupulous dealer to simply create their own gemological lab on paper and make it appear that they have got certified products. When, in fact, the products are being grossly misrepresented. This includes rubies as seen below. This official looking U.S. Gemological Laboratory report appraises this ruby bracelet at US$9,672.00, when rubies of the quality shown can be easily obtained for around $20.00 each. A cursory look at sales on Ebay verifies the extent of this issue that the industry and government continue to turn a blind eye. All one needs to do is count how many sales these operators make to understand the gravity of the problem. The impact on consumer confidence in our industry is dire.

Conclusion

We have obviously just scratched the surface of this topic in this article. Qualified jewelry appraisers need to do a lot of additional research and get a lot of experience with many  rubies to truly be qualified to appraise rubies accurately. However, this is a good starting point for those just now getting into the gemstone industry, or those interested in rubies as a new revenue stream. It is my hope that you will use this information as a portal to reach higher levels of study and to become successful in marketing this very important gemstone.

Robert James FGA, GG
International School of Gemology