Ruby is the red variety of corundum, coloured by chromium, and every other colour of the same mineral is called sapphire. For centuries the finest stones have come from the Mogok valley in Myanmar, whose top colour is nicknamed pigeon's blood, while Mozambique is now a major modern source. Ruby is the birthstone for July and one of history's most storied gems; ironically, several famous rubies in royal crowns, like the Black Prince's Ruby, later turned out to be red spinel. Some rubies with fine silky inclusions show a six-rayed star when cut as a cabochon.
At 9 on the Mohs scale, ruby is the second-hardest natural gem after diamond and has excellent toughness, so it genuinely is a lifetime daily-wear stone. The vast majority of rubies are heat treated to improve colour and clarity, a stable, accepted practice that should always be disclosed; glass-filled rubies also exist, cost far less, and need much gentler care. Certification matters at this level, and every stone we sell is genuine. Untreated heated rubies clean up happily with warm, soapy water.
Red spinel fooled royalty for centuries, garnet is the classic budget red, and ruby zoisite carries real ruby crystals in green stone.
