Red as love, passion, power and fire, the ruby radiates warmth and life. In the fascinating world of gems, the ruby is king and imposes its law!
Since ancient times, the ruby is one of the most precious stones. It is also one of the rarest, especially when it combines color, brilliance and clarity...
Ruby belongs to the corundum family, (aluminium oxide, AL2O3), the most abundant family of gems, to which sapphire also belongs. Pure corundum is colorless. It is the traces of iron, titanium, chromium, cobalt or vanadium which color the stone, in blue, pink, purple or red...
Corundum, sapphires and rubies, have a hardness of 9 on the Mohs scale, they are the hardest gems after diamond. Corundum can only be scratched by diamonds or other corundums.
Its refractive index, which measures the brilliance of gems is high, 1.74 to 1.76. It is a birefringent crystal, which means that it splits the rays of light that pass through it.
To qualify as a ruby, corundum must contain sufficient chromium. Pink, red or orange corundum that does not contain chromium is called pink, red or orange sapphire....
Until the 19th century, all red stones, rubies, garnets or spinels were called rubies, i.e. "red stones" or carbuncles "small embers".
Thus the famous "Black Prince's ruby" which has adorned the British crown for some centuries is in fact a magnificent spinel. And many "rubies" present in the treasures of museums or churches often turn out to be spinels or garnets when analyzed.
Get me some chrome...
Chromium is a very rare element on our planet, and even though chromium is necessary for corundum to give it its red color, its presence causes cracks and fractures in the crystal... This explains why very few stones have been able to crystallize uniformly and reach considerable sizes. Rubies of more than 3 carats are very rare (30 to 50 times rarer than diamonds according to the specialist Jack Abraham) and the prices per carat of the luminous and richly colored stones, largely exceed the price of the diamond.
The ruby symbolizes passionate feelings
Ruby red... The most important element for a gemstone is its color. The red of beautiful rubies is incomparable. Warm and flamboyant.
It is symbolically associated with blood and fire, heat and life. The ruby is therefore more than a colour, it has always accompanied the expression of passionate love.
Origin of rubies in the world
The best known deposits are located in Burma (Myanmar).
These deposits have been known since antiquity. The mines in the Mogok region produce rubies that often have a slightly pinkish hue. The mine of Mong Hsu, in the north-east, is today the most important. This mine produces bicolored stones, with a purplish-black core and a bright red periphery. Luckily, simple heating turns the dark hue into a deep red, opening up the jewellery market for these beautiful stones, which can weigh up to 3 carats.
Thailand has produced some beautiful rubies, often of a fairly dark hue. But the production there has become very low. Bangkok remains the hub of the ruby trade, with Thai traders having mastered this market and acquiring much of the world's rough production that is cut in Thailand.
Viet Nam produces rubies of a quality close to those of Burma; this is explained by their same geological formation. The first rubies were discovered in Luc Yen, northeast of Hanoi, in 1986. Vietnamese rubies range from light pink to the most intense red.
Rubies are found in northern Pakistan, Kashmir, Tajikistan, Laos, Nepal, and Afghanistan. In India also, rather large specimens but very included, and thus cut in ball or cabochon.
Madagascar also provides rubies. The main mines are located in Andilamena and in the regions of Tulear and Fionarangsoa.
Thanks to the geologist John Saul who discovered the first ruby mine in East Africa, Kenya and Tanzania are now among the countries producing rubies and of very beautiful color.
What is the most beautiful red for a ruby? That is the question!
The shades depend very much on the origin. When we talk about Burmese red, we usually refer to the most intense red with a slight bluish tinge, but this does not mean that the stone has a Burmese origin. This color is sometimes called pigeon's blood, but Burmese red would be more accurate. Connoisseurs will immediately associate it with Mogok rubies, or at least with the high quality stones found there. But everyone will have their own favourite red, whether it is carmine or bluer.
Colour above all else
Color is the most important characteristic of a ruby and transparency is secondary, so inclusions do not alter the value of a ruby as long as they do not remove its transparency or if they are not located in the heart of the table. (A reddish brown ruby with no transparency will have very little financial value).
Some rubies have a silky sheen. This phenomenon is due to the presence of rutile needles. When the needles align with the hexagonal structure of the crystal, they form a six-pointed star. The stone is cut into a cabochon to make it appear to glide over the surface of the "star ruby". This is one of the cases where inclusions, far from making a stone lose value, make it even more precious.
Generally speaking, some inclusions are like a fingerprint, proof of the natural origin of the stone. It is the cut that is essential, because only a perfect cut will enhance the color and pay tribute to its beauty.
A perfect ruby is as rare as perfect love... When you find it, don't let it go!
In 1992, while visiting Namibia, I was buying stones from an elderly dealer in Windhoek. While I was examining tourmalines with a dichroscope, he asked me what my device was used for. I answered that it allowed me to distinguish very quickly the birefringent stones (which split the light beam) from those which are not and in particular the glass.
"He said, "Could it be used to recognize rubies?" he continued, "for I am mining. I replied that my dichroscope would be able to distinguish rubies from other red stones such as garnet or spinel, or even glass, because the latter do not split the light beam. But it would not be used to distinguish natural rubies from synthetic rubies." At the end of our conversation, I left my camera with him and received a small tourmaline as a gift.
A month later, back in Paris, I received a small but dense package, entirely covered with stamps. I unwrapped it and found, wrapped in newspaper, a smoky quartz in the shape of a sceptre with inclusions of black tourmalines. A good kilo! My device must have been successful!
File made from the International Coloured Gemstone Association website www.incolor.org and from Fred Ward's article in National Geographic.