Fine ruby is undoubtedly one of the most valuable gemstones. Many times rarer than colourless diamonds fine rubies have it all – extraordinary colour, outstanding brilliance and a hardness that is second only to diamond. And so rare is this combination that in recent months we have seen very high examples from Africa on offer for USD50,000 per carat.
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 colourless and it is the slight traces of elements such as chrome, iron, titanium or vanadium that are responsible for the colour. Only red corundum is entitled to be called ruby with all other colours being classified as sapphires. The close relationship between the ruby and the sapphire has only been known since the beginning of the 19th century – until then red garnets or spinels were also thought to be rubies. That 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
For a long time India was regarded as the ruby’s classical country of origin. In the major works of India literature, a rich store of knowledge about gemstones has been handed down over a period of more than two thousand years. The term “corundum”, which we use today is derived from the Sanskrit word “Kuruvinda”. The Sanskrit word for ruby is “ratnaraj”, which loosely translates as “king of gemstones”. Today, rubies still decorate the insignia of many royal households, but they may not all genuine rubies due to confusion with other stones, in particular spinel.
The most beautiful ruby-red refers to the “Burmese ruby” – the highest quality of all. Stones from the famous deposits in Myanmar are a rich, full red with a slight hue. The colour 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. Sri Lankan rubies, which have now become very rare, are mainly light red, like ripe raspberries. Colour is a ruby’s most important feature, its transparency is only of secondary importance. Inclusions do not impair the quality of a ruby unless they decrease the transparency of the stone or are located right in the middle of its table. On contrary, inclusions within a ruby could 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, however, essential and rubies of more than 3 carats in size, and quality, are very rare.
Some rubies display a wonderful silky shine, the so-called “silk” of the ruby. This phenomenon is caused by very fine needles of rutile. And now and then one of the rare star rubies is found. Here too, the mineral rutile is involved: having formed a star-shaped deposit within the ruby, it causes a captivating light effect known by experts as asterism. If rubies of this kind are cut as half-dome shaped cabochons, the result is a six-spoked star that seems to glide magically across the surface of the stone when the latter is moved. Star rubies are precious rarities. Their value depends on the beauty and attractiveness of the colour and though only to a lesser extent, on their transparency. Fine star rubies, however, should always display rays that are fully formed all the way to the imaginary horizontal line that runs through the middle of the stone, and the star itself should be situated right in the centre.
Damian By Mischelle ..