The September Birthstone: Sapphire's Symbolism and Significance
Sapphire is September's birthstone — and one of the oldest, most storied gemstones in human history. Worn by royalty for centuries and second only to diamond in hardness among gemstones used in fine jewelry, sapphire has earned its place in engagement rings, eternity bands, and heirloom pieces. This guide covers what sapphire is, how to evaluate one, and what makes a sapphire genuinely worth wearing for a lifetime.
In short: Sapphire is the September birthstone — corundum colored by trace iron and titanium (blue) or other elements (pink, yellow, padparadscha), at Mohs 9 hardness, second only to diamond. Top Kashmir 1.00ct+ stones exceed $50,000 per carat; Ceylon and Madagascar $1,000-$8,000. Sapphire also marks the 5th and 45th wedding anniversaries and symbolizes wisdom, royalty, and fidelity.
What is sapphire
Sapphire and ruby are both varieties of the mineral corundum (crystallised aluminium oxide). Pure corundum is colourless. Trace elements determine the color: chromium produces ruby (red corundum), iron and titanium produce the classic blue sapphire, and other trace elements produce pink, yellow, green, orange, purple, and even color-changing sapphires. By gemological convention, only red corundum is called ruby; every other color is sapphire.
Hardness and durability
Sapphire scores 9 on the Mohs hardness scale — second only to diamond and significantly harder than every other commonly-set gemstone. This is why sapphire works exceptionally well in engagement rings and daily-wear jewelry: only diamond can scratch it, and it resists chipping in normal wear. Princess Diana's famous sapphire engagement ring (now worn by the Princess of Wales) has held up to four decades of regular wear precisely because of corundum's durability.
