Introduction: The term ruby is reserved for corundums of a red color, with other colors called sapphire. In Asia, pink corundums are also considered rubies. Outside of Asia, such gems are generally termed pink sapphires.
Color: Pink-Red to Red to Purple-Red, also Orange Red, and Darker Wine-Red varieties.
Clarity: In terms of clarity, ruby tends to be less clean than sapphire. Buyers should look for stones which are eye-clean, i.e., with no inclusions visible to the unaided eye. In the case of some rubies, extremely fine silk throughout the stone can actually enhance the value. Many rubies also display a strong red fluorescence to daylight, and this adds measurably to the beauty of this gem. While a certain amount of silk is necessary to create the star effect in star ruby, too much silk desaturates the color, making it appear grayish. This is not desirable.
Cut: In the market, sapphires are found in a variety of shapes and cutting styles. Ovals and cushions are the most common, but rounds are also seen, as are other shapes, such as the heart or emerald cut. Slight premiums are paid for round stones. Cabochon-cut sapphires are also common.
Moh’s hardness: 9
Specific Gravity: 4.0
Refractive Index: 1.76-1.78
Countries of Origin: The earliest source for ruby as well as sapphire– also classified as a corundum stone– is in Sri Lanka. The world’s finest rubies come from the Mogok valley of Upper Burma. The range of colors in Burmese rubies start from vibrant pink red through orange red, from the deep “pigeon’s blood” red, to purple-red. The untreated Mogok stones remain the most prized. You can find Rubies in Sri Lanka, Thailand, Vietnam, Africa, and Burma.
History, Literature and Lore: During the Middle Ages, the ruby was believed to have an inner fire that could not be concealed. Marco Polo, in his “Book of Marvels,” said that the Kublai Khan would not part with a treasured ruby even when offered an entire city in exchange. In the 16th Century, Camillus Leonardus wrote that ruby would preserve its owner’s health, remove evil thoughts, control amorous desires, dissipate pestilential vapors and reconcile disputes. Another belief was that ruby could warn its owner of impending misfortune by becoming dull and dark. By the time of the Renaissance, only the wealthiest individuals could dream of owning a ruby. It remains today the most valuable gemstone.
How To Choose: After diamond, Corundum is the hardest mineral. Color quality is the key factor in judging a ruby; while flaws diminish a gem’s value, a fine-colored ruby is considered of high quality even if a minor flaw exists; the purest red is the ideal, with no secondary colors of purple or brown, Large rubies are even more rare than large diamonds, so the value of ruby, more so than other gems, increases with weight. We at INTA Gems will be more than happy to help you choose the best stone for you!