The ruby is one of the most beautiful and valued gemstones used to adorn the most elegant and expensive jewelry and artwork. This stone is a variety of corundum (a mineral consisting of aluminum oxide), and its magnificent red color is the result of chromium admixed with the basic corundum composition. Rubies, as well as other corundum stones, are almost as durable as diamonds. A natural ruby can contain needle-like rutile inclusions lined up in parallel with the facets of the stone, creating a six-point star-like image. Such stones are called star rubies and are more valuable than clear rubies.
As a rule, pure rubies are small. Large rubies are very rare, and they are even more valuable than diamonds. Depending on the deposit location, the color saturation and the tint may vary distinctively. The classical blood-red rubies come from Burma. Siam rubies are always violet-red and brownish-red, and Ceylon rubies are lilac-red and violet-red. The most appreciated ruby colors are the scarlet Burman rubies, then come the lilac and violet rubies, while the least valued are the brownish stones.
Besides its hue, the ruby is also valued for its color consistency and saturation. The most expensive rubies are the uniform colored, medium-dark rubies while uneven color and over- or under-saturation decrease a stone's value. Rubies are usually diamond-cut – this cut type emphasizes primarily the color depth because the shine of a ruby is a less important quality.
The largest known ruby is the 2,475 carat (459 g or 16.2 oz) “Rajaratna Ruby,” which was unveiled to the world by its owner Mr. G. Vidyaraj of Bangalore, India, at the end of the year 1986. At that time, it was considered to be the world’s largest ruby as well as the world’s largest star ruby and was appropriately named the “Rajaratna Ruby,” which in Sanskrit means “The King of Rubies.” The most famous star ruby (the one with the rutile inclusions) is called the Rosser Reeves Star Ruby. It was found in Sri-Lanka and it weighs 138.7 carat (27.3 g or 0.97 oz).
There are also many famous large non-star rubies, such as these from Tanzania: the 8,500 carat Liberty Ruby carved in the shape of the US Liberty Bell, the 22,000 carat Mercy Ruby, and the Good Samaritan ruby measuring 15.9 by 13.3 cm (6.25” by 5.25”).
There is a long-held belief that rubies protect their owner so wearing them on a daily basis can help to prevent accidents and bad luck. The ruby is also believed to be helpful in reconciling conflicts and eliminating nightmares, as well as making its owner lucky in love, lively, and optimistic. In the Middle Ages, rubies were thought to make their owner as wise as a snake, as strong as a lion, and as courageous as an eagle.