Nature lavished her finest blues upon sapphires, the “Gem of the Heavens.” Although the word “sapphire” itself means blue, the gem is found in nearly all the colors of the rainbow.
Blue sapphire was called hyacinth until the Middle Ages. When mineralogists discovered that it was a member of the corundum family and existed in a variety of colors, they renamed the blue stone sapphire. They named other gems according to their colors, such as green sapphire, yellow sapphire, and pink sapphire. Only two stones retained their own names: ruby for red sapphires; and padparadscha (“lotus-blossom” in Sinhalese) for the pinkish-orange red gems.
The traditional blue color is described as cornflower blue or Kashmir blue after the region in India where blue sapphires were first mined.
Blue sapphires have always been connected with the sky and vision. Ancient people believed that the Earth sat upon a huge sapphire, which reflected its color to turn the sky blue. Many believed that sapphires repelled envy and the spirits of darkness while attracting the spirits of light. Others think their power is restrained to merely revealing liars. Early physicians fed their patients powdered sapphires to cure insanity. Travelers wore sapphires to protect against accidents while enroute. Those who wear sapphires are usually wealthy, as fine sapphires are valued about the same as diamonds.
Many believe that the Ten Commandments were carved on a sapphire, making it a sacred stone. Sapphire became the gemstone of choice for priests and is still often used in ecclesiastical jewelry. Kings also chose sapphires as symbols of their faithfulness and wisdom.
Corundum, the mineral from which all sapphires are formed, is extremely abundant and found worldwide. Corundum is the second hardest natural substance known. Only diamonds are harder. Corundum is also very tough–it won’t chip or crack easily. That’s why sapphire rings are so popular–they’ll stand up to daily wear in an exposed position.
In its pure state, corundum is colorless. Minute amounts of impurities provide the vivid hues. Titanium creates blue; chromium produces rubies; and iron turns corundum yellow.
Corundum ore yields only a very small percentage of gems. Padparadscha is the rarest, making it very expensive, with quality stones selling for as much as $10,000 a carat. On the other end of the scale is commercial corundum, an inexpensive abrasive mined for industrial use. Australia, China, Myanmar (Burma), and the United States presently mine gem-quality corundum.
Synthetic sapphires have been successfully manufactured since the early 1900s. They are indistinguishable from natural stones, except to experts. Similarly colored stones may also be sold as imitation sapphires. Sapphires are also easily mimicked in glass.
Most genuine sapphires today owe the purity and clarity of their colors to heat treatment. Others have been irradiated to improve their color. Heat treatment is permanent; colors enhanced by irradiation may fade.