Defined as corundum in any color other than red - due to the fact that red corundum is instead referred to as ruby - sapphire is one of the four gemstones previously thought of as “precious”. However, this term is seldom used today.

The name sapphire is derived from the Greek word for “blue”, and this remains, by far, the color with which it is most associated. In fact, it is customary within the gem trade to only use the non-prefixed term in isolation when referring to a blue stone.

While India’s Kashmir region is history's most revered blue sapphire source, today’s finest royal blue and lighter cornflower blue stones are found in Myanmar and Sri Lanka respectively, with Madagascar having become the primary producer in terms of quantity. However, most of the lower-quality inky blue material is sourced from Australia, Nigeria or China.