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 jewellery, 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 September birthstone — a corundum gem, Mohs 9 (second only to diamond), symbolising wisdom, royalty and faithfulness. Fine Kashmir and Ceylon blue sapphires reach £3,000-£15,000+ per carat above 2.00ct; commercial blue sapphires start at £150-£500 per carat. Lab-grown sapphires offer identical chemistry and colour for 70-90% less. Sapphire suits daily-wear engagement rings thanks to its hardness.
What is sapphire
Sapphire and ruby are both varieties of the mineral corundum (crystallised aluminium oxide). Pure corundum is colourless. Trace elements determine the colour: 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 colour-changing sapphires. By gemological convention, only red corundum is called ruby; every other colour 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 jewellery: 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.
