Sapphire is the birthstone for September and the gem of the 5th and 45th anniversaries.
Blue sapphire belongs to the mineral species corundum. It can be a pure blue but ranges from greenish blue to a violet-blue. The name “sapphire” can also apply to any corundum that’s not red and doesn’t qualify as ruby.
Sapphire is a durable stone that’s the best known blue gem, as well as being available in most colors.
Besides blue sapphires, there is another kind in the family called “fancy sapphires.” They come in violet, green, yellow, orange, pink, purple, and intermediate hues. There are also sapphires that show combinations of different colors. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can also be gray, black, or brown.
A special pinkish-orange sapphire color is called Padparadscha, which means “lotus flower” in Sinhalese, the language spoken in Sri Lanka. Sri Lankans have a special fondness for the color that’s traditionally been linked with their country.
Fancy sapphires are generally less available than blue ones, and some colors are scarce, especially in very small or very large sizes. Corundum is actually colorless in its purest state and rare. Colorless sapphires were once popular diamond imitations, and they’ve staged a comeback as accent stones in recent years.
Another type of sapphire is the Star Corundum, which can show a phenomenon called asterism or the star effect. This phenomenon usually appears as a six-ray star pattern across a cabochon-cut stone’s curved surface. The star effect comes from white light reflecting from many tiny, oriented, needle-like inclusions.
Blue and fancy sapphires come from a variety of exotic sources, including Madagascar, Tanzania, Sri Lanka, Myanmar, and Australia. Tons of earth and countless hours of labor are needed to bring a gem from mine to market.
In folklore, history, art, and consumer awareness, sapphire has always been associated with the color blue. Its name comes from the Greek word sappheiros, which probably referred to lapis lazuli. Most jewelry customers think all sapphires are blue, and when gem and jewelry professionals use the word “sapphire” alone, they normally mean “blue sapphire.”
Traditionally, sapphire symbolizes nobility, truth, sincerity, and faithfulness. It has decorated the robes of royalty and clergy members for centuries. Its extraordinary color is the standard against which other blue gems—from topaz to tanzanite—are measured.
In ancient Greece and Rome, kings, and queens were convinced that blue sapphires protected their owners from envy and harm. During the Middle Ages, the clergy wore blue sapphires to symbolize Heaven, and societies believed the gem attracted heavenly blessings.
Sapphire has been linked with royalty and romance for centuries. The association was reinforced in 1981 when Britain’s Prince Charles gave a blue sapphire engagement ring to Lady Diana Spencer. Her sapphire ring helped connect modern events with history and fairy tales. It is the world’s most famous engagement ring and now belongs to Catherine, Duchess of Cambridge, who is more universally known as Kate Middleton.
- MINERAL: Corundum
- CHEMISTRY: Al2O3
- COLOR: Every color but red
- REFRACTIVE INDEX: 762 to 1.770
- BIREFRINGENCE: 008 to 0.010
- SPECIFIC GRAVITY: 00
- MOHS HARDNESS: 9
(GIA Gem Encyclopedia Sapphire, 2015)