The sapphire is a corundum, an aluminum oxide with a trigonal crystal structure, in the same family as the ruby. The only difference between a ruby and a sapphire is simply the color. A red corundum is a ruby. Other colored corundums are called sapphires, which come in many colors, the most well known being blue. Because sapphires are available in so many colors, they are the most important and versatile of all the gemstones. Rubies and sapphires are said to be prized just under the level of diamonds because of their hardness. Diamonds are listed as a ten in terms of hardness, sapphires as a nine. The attribute of hardness of the sapphire makes it a perfect choice for jewelry that needs to stand up to everyday wear, such as in rings or bracelets.
The gem’s inclusions reflect light that yields a faint sheen referred to as “silk.” The most transparent, colorless variety of sapphires are known as “Leucosapphire.” Some have streaks of pale color inside, some have that slightly silky sheen and in strong light, their color intensifies. Sapphires are usually given round or oval cuts but rectangular or square cuts are also possible.
Fine sapphires are most available under two carats, but they can also be found in sizes from five to ten carats. The color of a sapphire is created by various amounts of iron and titanium in the stone, the combination of which produce varying colors. Heat treatments have become common in recent years, as a way of improving color as the beauty of a sapphire is judged by the richness and intensity of its color. The most desirable color sapphire is blue, and the most desirable shade of blue is referred to as “cornflower blue.” It is neither light nor dark blue. Like rubies, sapphires can come with a natural six rayed star inside, which is called the “star sapphire” and is extremely rare. The star sapphire reflects light, showing a glittering star with six points. These special stones possess the deep blue color of the finest sapphire. The gray, blue-gray, and white “star” sapphires frequently show a more distinct star. In the gemstone trade, these are also referred to as “Linde,” pronounced “Lin-dee.”
Sapphires also come in violet, dark gray, orange, yellow, pink, green and black, which tends to be relatively inexpensive. These different colored sapphires are referred to as “fancy sapphires” and are often less expensive than the blue ones, yet equally as beautiful and a fine alternative to blue. A rare colored kind of sapphire is called “Padparadscha,” which means “Lotus color.” It is the only color sapphire given it’s own name besides the ruby. This stone is orange and pink simultaneously and can be very expensive.
Blue sapphires come from Burma and Kashmir, where the blue tone is the most pure to the true spectral blue, and the stones tend to have a unique velvety luster. Sapphires from Sri Lanka are a less deep shade, almost a pastel blue. Many sapphires also come from Australia, which are dark blue but with a slightly green undertone, as those from Thailand. These tend to be less expensive than those from Burma, Kashmir and Sri Lanka.
Sri Lanka is the world’s largest producer of sapphires over 100 carats and they are a lighter shade of blue. Stones from the Mogok valley in Burma are very highly regarded, and many star sapphires come from there. Dark blue sapphires are found in New South Wales and Queensland Australia. Gems from Western Cambodia are also highly prized, but usually small. China and Nigeria produce dark stones and in the US, Montana sapphires are prized for their natural metallic blue color. They are not subjected to any treatment, as sapphires are normally heat treated to eliminate impurities and enhance the color and clarity- this treatment is usually permanent. Sapphires also come from Tanzania, Brazil, Kenya, Malawi and Columbia.
Because of their hardness, Sapphires can be cleaned in almost any way. Warm, soapy water is best, though you might also try ultrasonic cleaners and steamers. You can also try using water with a touch of ammonia in it. If you have a fracture in your sapphire or own a star sapphire, do not use mechanical cleaning methods as a sapphire can shatter with one single blow, if hit sharply. This may be especially risky if the stone has inclusions, which weaken the crystal structure. As with most valuable stones, avoid doing heavy work or coming into contact with chemicals while wearing your stone, as they can damage your settings.