Ruby

Origin of name: from Latin ruber, red

Synonyms and trade names: none. There is, however, a plethora of trade names for other red gemstones containing the term "Ruby". The intention is, of course, to ennoble its bearers, mostly garnets.

Bohemian Ruby: Pyrope Garnet from the Czech Republic San Diego Ruby:  Rubellite (red Tourmaline) from San Diego, California
Siberian Ruby: Rubellite (red Tourmaline) from Russia

Can be confused with: many other red gems, as well as synthetics and glass

Burma (Myanmar) and Vietnam produce red Spinel of fine Ruby colour.

The synthetic Rubies encountered most frequently in the trade are so-called Verneuil Rubies. The process was patented in 1902 and mass production started as early as 1904. Thus the fact that a ring was inherited from great grandmother is no proof of natural origin!

In general the detection of Verneuil synthetics is no big challenge for the experts.

Unusual Synthetic Verneuil Cabochon
Normally synthetics are facetted

Other synthetics, which are produced by more sophisticated and expensive methods, can pose serious problems, though. Careful microscopic studies of inclusions mostly lead to successful identification, where loupe and experience do not suffice. In very rare cases advanced technology like element analysis by e.g. x-ray diffraction or Raman-Spectroscopy has to step in.

The good news: the danger to fall for a high-end synthetic ruby (or sapphire) has diminished significantly over the last years. Due to enormous production costs and probably also due to unsatisfying economic success, several companies have stopped production or closed down altogether.

Because of the high value Rubies are amongst the gems that are synthesized and imitated most often. The earliest synthetic gems known were the so-called "Geneva Rubies" which were produced as early as 1885 and sold as genuine by a Geneva dealer.

In 1886 Paris jewellers gave the Sorbonne University some Geneva Rubies for examination. A Professor Friedel found them to possess the same density, hardness and optical properties as natural rubies. However, under magnification Friedel found numerous gas bubbles typical for glass and rightly concluded that the rubies were produced by some kind of high-temperature fusion process.

After it was decreed that these rubies were not to be sold as natural, claims were made that the stones were indeed produced by a flame-fusion process but that the starting material was fragments that were left over during the cutting of natural rubies.

For the next twenty years Geneva Rubies were being sold as "Reconstructed Rubies" at prices of $25 to $40 p.ct. until they were finally pushed off-market by the far superior Verneuil synthetics in 1904.

Localities: the most famous and most important locality is the Mogok area in Burma (Myanmar).



Some Burma Rubies of fine quality Another important source is Vietnam. Because of the very similar geology, Vietnamese Rubies are very hard to distinguish from Burma Rubies, at least at first sight. However, due to increasing fraud with synthetic rubies, many traders from Thailand, were most of the world's Rubies are cut and traded, retired from the Vietnam Ruby business so that today Vietnamese Rubies do not play a major role on the market. Sri Lanka has been a Ruby source for many centuries, yielding gems of slightly lighter tone and sometimes a distinctly pinkish hue.


"Ceylon" Ruby Rubies from Thailand, still called Siam Rubies in the trade, occur in iron-rich basalts. The high iron content often gives Thai Rubies a brownish tinge which makes them less desirable and harder to sell.


Thai Rubies in different shades of red
The center stone weighs 20.85cts! On the African continent there are several Ruby deposits but only a few that yield high quality stones.


Untretaed Tanzanian ruby
mined 1987


Three leaves, hand-carved in India from African rough material

Without a doubt the most spectacular African Rubies come from a source discovered near the Tanzanian village of Winza in 2007. The colour of these Rubies needs no improvement but unfortunately it seems that all hopes for prolonged and sustained production have dwindled. According to our knowledge of summer 2010, the Winza mines are no longer productive. Malawi and Mozambique occasionally produce fine quality Rubies but not enough to play a significant role in the world's Ruby trade. Last but not least Kenya shall be mentioned as a source of vast quantities of Rubies of mostly inferior quality. Much of the Kenya Ruby is fashioned into cheap cabochons.

Kenya also produces large quantities of a green, red and black mixture of Ruby, Zoisite and Amphibole which occasionally is made into cabochons. More often, however, the material is carved into small figurines.

With Rubies one is much more tolerant. Even flat stones that hardly show any brilliance will be accepted if only the colour is good enough.

Not so with Ruby. The famed pigeon blood red, which is a red as pure and vivid as possible, has been the most desired and most expensive colour for centuries. Any pinkish or, worse, brownish tinge is punished by a decrease of value.

Of course the price per carat decreases along with clarity but in contrast to, say, sapphire, even milky rubies will eventually find a buyer.

By heat-treating Rubies many undesired bluish or brownish tinges can be reduced or sometimes made to disappear altogether. The process is legitimate. According to CIBJO rules it has to be disclosed at the point of sale. From a certain size and quality non-treated Rubies command a significantly higher price than treated ones. Such stones nowadays are almost always offered with a certificate of an internationally renowned laboratory.

Glassfilled Ruby: the market is being flooded with glasfilled "Rubies". The source material is very low grade ruby, mostly from Madagascar. The surface-reaching fissures of this rough are filled with lead-glass which improves transparency dramatically.
Of course this treatment must be disclosed at the point of sale but unfortunately this regulation often either ignored completely disclosure is insufficient. Merely describing a glass-filled Ruby as "treated" is  misleading and, in our view, bordering to fraudulent.

Attention: we can only warn you to buy such "Rubies", however temptingly cheap they may be. Many of these stones contain more glass - up to 70% ! - than Ruby. So, actually in these cases one should speak of glass with ruby content. Indeed, some international laboratories call such stones "composite material".
Furthermore the fillings can be quite short-lived. It has been found that plain lemon juice suffices to etch the lead-glass...



Some glassfilled Rubies weighing up to 8cts Handling: due to the great hardness and the absence of cleavage Ruby generally is easy to work with.

However, Rubies can be heat-sensitive. High temperatures can cause a colour change.

Most Corundums have mineral and liquid inclusions. These have higher expansion coefficients than their host. Thus they expand more upon heating which can produce cracks or even total destruction.

Worth Knowing: Ruby is the undisputed king of coloured gemstones, at least when it comes to value. In February 2006 Christie's scored a whopping 425.000 dollars per carat for a 8.62cts Burma Ruby thus shattering the old record of "merely" $275.000 per carat, paid for another 8ct Burma Ruby in the year before.

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