Sapphire, most recognized for its blue color, is the official birthstone of September. It is also used for the 5th and 45th anniversary.
Sapphire is the same mineral, corundum, as Ruby. Although Sapphires are most commonly blue, any color of corundum that is not Ruby Red is considered a Sapphire. Unlike some other gemstones, all color variations of sapphires are natural and not created through heat or pressure treatments. This makes those "fancy sapphires" rarer and often more valuable.
Sapphires were once believed to have protective abilities or healing powers. This included protection from poison, healing of rheumatism, blindness, colic or even mental illness. Some cultures would wear Sapphire pendants to prevent envy or guard chastity. Throughout history, Sapphires were often the go to gemstone to use in mystical enchantment.
Mineral Group: Corundum
Colors: Blue (all colors except red)
Refractive Index: 1.762 to 1.770
Birefringence: 0.008 to 0.010
Specific Gravity: 4.00
Mohs Hardness: 9