Ruby
Corundum group
Color: red in various hues
Moh's hardness: 9
The ruby is named after its red color "rubens" in Latin means red. For thousands of years, the ruby has been considered one of the most valuable gemstones on earth. Rubies are extremely rare and can be more valuable than diamonds in finer qualities.
Ruby is the red variety of the mineral corundum. Pure corundum is colorless. Slight traces of elements such as chrome, iron, titanium or vanadium are responsible for the color. Corundum gemstones have excellent hardness. On the Moh's scale their score of 9 is second only to that of the diamond. Only red corundum is entitled to be called ruby, all other colors are classified as sapphires.
Chrome was the element which gave the ruby its wonderful color; it was also responsible for causing a multitude of fissures and cracks inside the crystals. Therefore, rubies of more than 3 carats in size are very rare. Larger rubies in good colors and with good clarity are so valuable that they achieve top prices at auctions, surpassing even those paid for diamonds in the same category.
The highest valued ruby is the "Burmese ruby", which displays a rich, full red with a slightly bluish hue. Rubies with this color typically occur in the famous deposits of Burma (Myanmar) but do not necessarily have to be of Burmese origin. The color of a "Burmese ruby" is regarded as exceptionally vivid and is said to display its unique brilliance in any light, natural or artificial. The so-called "Siamese ruby" has an elegantly muted deep red considered second in beauty only to the Burmese color. "Ceylon rubies", which have now become very rare, are mainly light red, like ripe raspberries.
Color is a ruby's most important feature. Its transparency is only of secondary importance so inclusions do not necessarily impair the quality of a ruby. 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.