September Birthstone: Blue Sapphire
Traditional Gift for 5th and 45th Wedding Anniversaries
The world’s most famous engagement ring is Kate Middleton’s and Princess Diana’s sapphire.
Besides blue sapphire and ruby, the corundum family also includes so-called “fancy sapphires.” They come in violet, green, yellow, orange, pink, purple, and intermediate hues. 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 even be gray, black, or brown.
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.
For centuries, sapphire has been associated with royalty and romance. The association was reinforced in 1981, when Britain’s Prince Charles gave a blue sapphire engagement ring to Lady Diana Spencer. Until her death in 1997, Princess Di, as she was known, charmed and captivated the world. Her sapphire ring helped link modern events with history and fairy tales.
- Mineral: Corundum
- Chemistry: Al2O3
- Color: Every color but red
- Refractive index: 1.762 to 1.770
- Birefringence: 0.008 to 0.010
- Specific gravity: 4.00
- Mohs Hardness: 9
Source: GIA Gem Labs