What are Rubies?


For thousands of years, the ruby has been considered one of the most valuable gemstones on Earth. It has everything a precious stone should have: magnificent color, excellent hardness and outstanding brilliance. In addition to that, it is an extremely rare gemstone, especially in its finer qualities.
Ruby is the red variety of the mineral corundum, one of the hardest minerals on Earth, of which the sapphire is also a variety. Pure corundum is colorless. Slight traces of elements such as chrome, iron, titanium or vanadium are responsible for the color. Only red corundum is entitled to be called ruby, all other colors being classified as sapphires. The close relationship between the ruby and the sapphire has only been known since the beginning of the 19th century. Up to that time, red garnets or spinels were also thought to be rubies. (That, indeed, is why the ‘Black Ruby’ and the ‘Timur Ruby’, two of the British Crown Jewels, were so named, when they are not actually rubies at all, but spinels.)
In really fine colors and good clarity, however,  rubies occur only very rarely in the world’s mines. The most important thing about this precious stone is its color. The red of a ruby may involve very different nuances depending on its origin. The range of those nuances is quite wide. For example, if the gemstone experts refer to a ‘Burmese ruby’, they are talking about the top luxury category. However, it does not necessarily follow that the stone is of Burmese origin. It is basically an indication of the fact that the color of the ruby in question is that typically shown by stones from the famous deposits in Burma (now Myanmar): a rich, full red with a slightly bluish hue. The color is sometimes referred to as ‘pigeon-blood-red’, but the term ‘Burmese color’ is a more fitting description. A connoisseur will immediately associate this color with the legendary ‘Mogok Stone Tract’ and the gemstone centre of Mogok in the North of Myanmar. Here, the country’s famous ruby deposits lie in a mountain valley surrounded by high peaks. Painstakingly, gemstones of an irresistible luminosity are brought to light in the ‘valley of the rubies’. Unfortunately, really fine qualities are quite rare even here. The color of a Burmese ruby is regarded as exceptionally vivid. It is said to display its unique brilliance in any light, be it natural or artificial.
Ruby deposits also exist in Vietnam, near the Chinese border. Rubies of Vietnamese origin generally display a slightly purplish hue. Rubies from Thailand, another classical supplier, however, often have a darker red which tends towards brown. This ‘Siamese color’ - an elegantly muted deep red - is considered second in beauty only to the Burmese color, and is especially popular in the USA. Ceylon rubies, which have now become very rare, are mainly light red, like ripe raspberries.
Straight after their discovery in the 1960s, rubies from Kenya and Tanzania surprised the experts by their beautiful, strong color, which may vary from light to dark red. But in the African mines too, fine and clear rubies of good color, purity and size are very rare. Usually the qualities mined are of a merely average quality.
Where color is a ruby’s most important feature, its transparency is secondary. Inclusions do not impair the quality of a ruby unless they decrease the transparency of the stone or are located right in the centre of its table. On the contrary: inclusions within a ruby could be said to be its ‘fingerprint’, a statement of its individuality and, at the same time, proof of its genuineness and natural origin. The cut is essential: only a perfect cut will underline the beauty of this valuable and precious stone in a way befitting the ‘king of the gemstones’.