Rough sapphires come in a barrel shape, tapered at the ends and larger in the centre. Most corundum in nature is heavily included and suitable only for industrial use, while gem-quality corundum is very rare. The other sapphire colours are caused by various mixes and proportions of iron, titanium and chromium.
In the case of chromium, the corundum turns red and gives us rubies. If the transition microelement is iron or titanium, the corundum turns blue, and we get blue sapphires. However, when minuscule traces of other minerals (often as little as 1%) mix with corundum, they turn it into various colours such as red, pink, blue, yellow, etc. They are formed beneath the earth’s surface under immense pressure and intense heat out of the mineral called corundum (aluminium oxide) which seeps into cracks in igneous or metamorphic rocks. Once the liquid cools, it turns into colourless crystals. The name sapphire comes from the Greek word “sappheiros” or the Latin word “saphirus”, both of which mean “blue”. Like diamonds, sapphires take millions of years to form, and no two natural sapphires will ever look the same. The birthstone of September, this deep blue gemstone has been adored for its colour, durability and beauty since ancient times. Sapphire is one of the four recognized precious gemstones and the second hardest mineral on earth after diamond.
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