An 18K white gold Engelbert ring set with a sapphire and round brilliant-cut diamonds.

Sapphires have been a source of fascination throughout history. In the medieval period, they were believed to protect against poison, fever, and skin diseases. Among natural gemstone materials, sapphire is second only to diamond in hardness. It possesses a high lustre and is prized for its colour. The combination of iron and titanium causes the blue colour that is most commonly associated with sapphires, although they appear in several colours. Sapphire is the birthstone for September.