The term "sapphire" comes from the Hebrew "sappîr", which means blue stone. In the past, it referred to various blue gems, such as lapis lazuli, from antiquity to the Middle Ages.

Around 1800, sapphire was recognized as a variety of corundum, just like ruby. Today, the name sapphire is used for all gem-quality corundum that is not red.

There are blue sapphires, but also pink, green or yellow sapphires... However, if the color is not mentioned, the word sapphire without a qualifier always means blue sapphire. The blue color of sapphire is attributed to the presence of iron and titanium. The violet color is due to vanadium, the yellow and violet to trivalent iron, the pink color to chromium, the orange color to vanadium and iron.

The most sought after color is a true cornflower blue.

The hardness of sapphire is 9.

Star sapphire is a sapphire whose asterism is due to the presence of inclusions of rutile needles crystallized at 60° or 120° in the stone. The star sapphire is cut in cabochon. Under the sun's rays appears a star of 6 branches most often.

Sapphire deposits are found in many places, the most significant being in Australia, Biramnia (Myanmar), Sri Lanka (Ceylon), and Thailand (Siam). Sri Lanka (Ceylon) has been supplying sapphires since ancient times. The renowned Kashmir sapphire deposits in India are now depleted. Large sapphires are rare.