Ruby

is the colour of love. It radiates warmth along with strong vitality. Red is also the colour of Ruby, king of gemstones. In the fascinated world of gemstones, Ruby is the uncontested sovereign.

Ruby has always been the most precious gemstone in the world. Even Diamonds seem ordinary in comparison with the value and the supreme beauty of this bright red gemstone. Named after the Latin word “ruber” (red) for its shade, Ruby is the quintessence of the liveliest of colours: the gemstone of desire, of passion, of courage and emotion…It has everything one expects from a precious gemstone: magnificent colour, excellent hardness, incomparable shine.  What is more, it is an extremely rare gem, especially in its finest quality.

Ruby belongs to the corundum mineral family, which is transparent in its pure form and allochromatic; its colouring is due to trace impurities that are not part of its basic chemical formula or to inclusions trapped in the crystalline network of the mineral. A full spectrum of colours is the result. This is why the beautiful red gemstone and its royal blue cousin have the same chemical composition of aluminium oxide. The red of the Ruby is caused by the presence of chromium, while the blue of the Sapphire is due to iron or titanium. Rubies, as well as Sapphires, also contain minuscule traces of other elements depending on the source of their deposits. For this reason, traces of iron can modify the pure red of Rubies and produce pinkish, purplish, orangey or brownish shades. 

Only red corundum has been authorised to carry the name Ruby; all the other colours are classed as Sapphires. The close relationship between Ruby and Sapphire was only discovered at the beginning of the 19th century. Prior to that time, it was believed that red spinels were also Rubies. (This is why the “Black Prince’s Ruby” and the “Timor Ruby”, two of the British crown jewels, were so called despite their being spinels and not Rubies.)

Beautifully coloured and transparent Rubies are rare. In quite a paradoxical manner, it is actually the chromium, its colouring element, which is responsible for its rarity. Millions of years ago, when these gemstones were created in the depths of the earth’s crust, it was chromium which gave Ruby its marvellous colour. But it was also a factor in the many fissures and cracks within the crystals. As a result very few Rubies benefitted from the right conditions – a perfect combination of aluminium oxide, the right temperature and pressure, with a very low degree of silicon – to grow damage-free to a considerable size and to crystallize in such a way as to form perfect gemstones. This is why Rubies with a size in excess of 3 carats are very rare. It is, therefore, not surprising that Rubies with very few inclusions, of good colour and size, reach very high prices, even exceeding those of Diamonds within the same category.

Some Rubies have a stunning, silky shine, justly named “silk”. This phenomenon is caused by very fine slivers of rutile. From time to time, the rutile crystals are deposited within the Ruby creating a captivating luminous effect which has been given the name asterism by experts. When such Rubies are cut en cabochon, the result is the appearance as if by magic of a six-pointed star on the surface of the stone when it is moved. Star Rubies are rare and precious. Their value depends on the beauty and the attractiveness of their colour and, to a lesser degree, their transparency. However, the finest star Rubies should always display fully formed rays, and the star itself must be located right in the centre. The colour of these star Rubies ranges from pale pinkish red to deep rosy pink via purple. As a general rule, the darker the crystal, the more visible the star, and vice versa. In practice, it is very unusual for a gemstone to possess both a colour and a star of equal beauty.

Ruby is found in every grade of transparency, from totally clear to opaque. Its transparency is affected by a wide variety of mineral crystals which, after minute observation, will often indicate to a gemmologist a manifest relationship with the country of origin of the gemstone.

With regards to the size of Rubies, a compromise in terms of ideal size is often made, because rough Ruby is very costly and that is why priority is given to conserving maximum weight once the gemstone has been cut. In consequence, Rubies are often cut asymmetrically, generally in symmetric proportion to the crown and the facets of the disproportionate angles of the pavilion, which does not necessarily diminish the shine or the final appearance of the gemstone. The largest Rubies are usually cut into oval or cushion shapes depending on the shape of the uncut gemstone, although the most imaginative shapes – pear, heart or emerald – are also possible.

Smaller Rubies are cut into many appropriate shapes such as round, oval, square, marquise, triangle, baguette, heart or emerald. More opaque, shimmering or star gemstones are cut en cabochon in order to bring out their colour, the cat’s eye effect (extremely rare) or the much sought-after six-pointed star (or rarer still, 12-pointed).

The cut of a Ruby is not as important as some other factors when it comes to establishing its price; it is, however, extremely important to obtain the best colour. If the faceted Ruby is not cut in the right direction of the crystal, it can produce a very ordinary colour instead of its lovely Ruby red, and this will drastically reduce its price. It is a real challenge to obtain a good cut, with the loveliest colour and minimal loss, without compromising the weight of this costly gemstone.

The cut is, therefore, essential: only a perfect cut will bring out all the beauty of this precious gemstone in a manner fitting for the “king of gemstones”. However, a really perfect Ruby is as rare as a perfect love. And one, just like the other, is priceless.

Ruby History and Legends

For a long time, India was considered to be the classical country of origin of Rubies. In the major works of Indian literature, a deep well of knowledge of gemstones was transmitted over a period of more than two thousand years. The term “corundum” used today derives from the Sanskrit “kuruvinda”. The Sanskrit word for Ruby is “ratnaraj” which translates along the lines of “king of precious stones”. And indeed, a royal welcome was given to it. When a Ruby of exceptional beauty was discovered, the Emperor sent dignitaries to collect the precious stone and an official royal ceremony of welcome was decreed. The Indians believed that he who offered Rubies to Krishna was assured of future reincarnation as Emperor. In the Hindu tradition, Ruby was one of the stones of the Navagraha (the stones representing the nine planets which had a cosmic influence over everything living on Earth): it symbolises the Sun (Ravi) and is linked to our soul.

In Biblical tradition, we also find many references to the venerable Ruby, more than to any other gemstone. The Book of Job declares that “the price of wisdom is above Rubies”. The Bible also says that only virtuous women are “more precious than Rubies”.

The Etruscans and the Greeks were the first Europeans to discover Rubies between 600 and 400 BC. It was at this time that the popularity of this fascinating gemstone began to grow in Europe, and it is from the Latin “ruber” (red) that the word “Ruby” takes its origins.

At the beginning of the 11th century, the Persian scientist al-Biruni reflected popular wisdom when he wrote that Ruby took “first place for its colour and its beauty” among all gemstones. Nine centuries later British writer Max Bauer, in his masterpiece, Precious Stones, from 1894, wrote “A clear, transparent and faultless Ruby of a uniform red colour is at the present time the most valuable precious stone known”. And yet, the value of a fine Ruby compared to other expensive gemstones was not as elevated in Bauer’s time as it had been previously. Around 1550, the Italian goldsmith Benvenuto Cellini reported that a Ruby of one carat of the finest quality cost eight times more than a Diamond of comparable quality.  In Bauer’s time, the same Ruby was only twice as expensive as an equivalent Diamond. However, a ratio of 2 to 1 between Rubies and Diamonds is impressive. The status conferred on Ruby at the time, that of the most precious gemstone, certainly helps in understanding why England took such a drastic measure as to invade and annex upper Burma in 1885, as soon as the country discovered that a French company had begun to extract this gemstone from the famous Ruby vein of Mogok – still the most celebrated and important source of Ruby today.

Since time immemorial, Ruby has featured among the most treasured possessions of reigning families and has been used as a jewel in crowns. Even today Rubies decorate the insignias of many royal families.

Ruby, one of the most ancient precious stones, is steeped in myth and symbolism. It was endowed with noble and magical powers by the ancient Hindus, Indians and Chinese, and later by the Christians, among other cultures and belief systems. A worthy ambassador of desire, devotion and passion, the Ruby is supposed to be a gemstone of prophecy and an antidote to poison, darkening in the face of imminent danger. It was believed that rubbing a Ruby against the skin restored youth and vitality. The owner of a precious Ruby was thought to be secure from harm and was assured of a life lived in peace and harmony among adversaries. It was also believed that it guaranteed good physical and mental health for life. Ruby also represented integrity, happiness, health, courage, romantic love, generosity, inspiration and was associated with the sun.

In modern tradition, Ruby is the birthstone of those born in July. It also represents 15th and 40th wedding anniversaries. It is also associated with the sign of Capricorn.

Ruby Sources

Myanmar (formerly Burma) is the most famous and important source of Rubies that are among the finest in the world. The mines date back to the Bronze Age, as can be seen from the discovery of ancient mining tools in the Mogok region. The mines of this region provide Rubies of a beautiful pure red or with light pinkish hues. A number of Rubies have been extracted from the mines of Mong Hsu in the north east of Myanmar, and most are of a very fine quality with a size often in excess of one carat. At first it was thought that these Rubies were hardly suitable for use in jewellery, because an untreated Ruby from Mong Hsu actually presents two colours: a purple, or even black, heart and a bright red periphery. It was only when it was discovered that the dark heart could turn deep red through heat treatment that the Rubies of Mong Hsu found their way onto the jewellery market. Today the mines of Mong Hsu are among the principal Ruby mines. They mostly supply Rubies of commercial quality that have been heat treated, in sizes between 0.5 and 3 carats. In fact, many Myanmar Rubies exude a red fluorescence under ultraviolet light, which intensifies the colour of the Rubies in daylight.
In 1992 a new and promising vein was discovered in neighbouring Vietnam, near the Chinese border. Dazzling Rubies with a light purple shade have been extracted and some are indistinguishable from the most beautiful stones of the mines of Myanmar. In fact, these two sources are probably part of the same geological formation. 
Rubies from Thailand – another traditional supplier – are often of a darker red, tending towards brown, although high quality gemstones of a very bright red are also found there. This “Siamese colour” – an elegant, soft and deep red – comes second in terms of beauty after the Burmese red, and is particularly popular in the United States.
Rubies from Sri Lanka are generally light red and have a pinkish red shade of ripe raspberries, although most have pastel tones and come under the shades of pink or purple.
Other veins of Rubies are found in the Hunza Valley in the north of Pakistan, in Kashmir, Tajikistan, Laos, Nepal and Afghanistan. India also extracts Rubies. Veins with fairly large crystals have been found near Mysore and in the state of Orissa. These Rubies have many inclusions yet they are eminently suitable for cutting into pearls or en cabochon.
There have also been major discoveries of Rubies in Madagascar, where very red and transparent specimens have been extracted in the Fionarantsoa region. Soon after their discovery in the 1960’s, Rubies from Kenya and Tanzania surprised experts with their beautiful, bright colour which ranges from light to dark red. However, in general in African mines, pure and transparent Rubies of good size and colour are extremely rare.

Ruby Value and Treatments

Ruby is the most precious gemstone in the corundum family, indeed one of the most precious in the world. The value of a Ruby is essentially based on its colour, size (in carats) and clarity. When it comes to star Rubies, they value is based on their general colour, transparency and the position, shape and shine of the star. A bright, strong and well-centred star against a background of a bright and clear red is the quintessence of the star Ruby. 

Rubies that have maximal red saturation, without shades of brown, and that are neither too dark nor too light, are the most sought-after. Rubies of this type usually come from Myanmar, tend towards pinkish or slightly purplish shades, and reach the highest prices on the market. Myanmar Rubies displaying irregular colour zoning will see their value reduced, even if the zoning is not visible from the table side of the stone. Inclusions, on the other hand, do not diminish the quality of a Ruby unless they lessen the clarity of the gemstone or are located right in the centre of its table. On the contrary: inclusions in Rubies can be viewed as “fingerprints”, an expression of their individuality and at the same time proof of their authenticity and natural origins.

One of the most important criteria when valuing a Ruby is its size. Big Rubies with beautiful colour in excess of 5 carats are extremely rare, and, in consequence, are the most precious. Even gemstones between 0.5 and 1 carat in the range of superior reds are relatively rare. However, smaller Rubies, less than 0.5 carats, are numerous in comparison and, depending on their colour, clarity and the quality of their cut, come at more modest prices.

More than 90% of Rubies that are currently available on the market have been treated to improve their quality. The most common treatments for Rubies are heat treatments in order to improve colour and transparency, and they are seen as a continuation of the natural process which took place within the earth’s crust when the Ruby was formed. The practice of heat treating gemstones is centuries old, although it has developed with the help of modern, sophisticated techniques. Depending on the desired result, temperature, heating and cooling times and atmospheric conditions will be controlled. Cut and polished Rubies are heated at temperatures between 800 and 1,800°C in an oxidising atmosphere, and are sometimes cooled rapidly in order to eliminate unwelcome shades of purple, blue or brown along with the natural “silk” of rutile. A Ruby that shows no sign of heat treatment is very rare these days.

Other treatments may be used on Rubies, but most are considered dubious, or even unacceptable, due to a combination of factors including surface penetration and the introduction of colouring, filling or destabilising agents. Among these, lead glass filling is noteworthy: filling in the fractures on the surface of the Ruby with what is commonly known as lead glass, which greatly improves the transparency of the stone and turns a Ruby that was originally unsuitable for commercial use into one suitable for use in the composition of costly jewellery. The colour of pale Rubies can also be improved by the addition of beryllium. Such treatments are superficial and once the stone has been re-polished and its natural colour becomes apparent, the disappointment will be great. Caution should therefore be exercised when purchasing from doubtful sources or little-known vendors. The only stable and permanent treatment for Rubies is heat treatment: it increases the potential value of the gemstone and is a completely acceptable practice in the gemstone business.