Besides blue, sapphires are also found in pink, yellow, orange, violet, green, as well as others which are colourless or contain other tones.
As with the blue sapphire, the colour of the stones is defined by the type of impurities present (vanadium for violet, chromium for pink, iron for yellow and green).
Most fantasy coloured sapphires are found in Sri Lanka.
Sapphire can be heat treated; stones that are too clear, too dark or with many inclusions can be modified by heating. This process boosts the colour and clarity.
Yellow sapphire is prized in jewellery, where its lively colour makes for easy combination with diamond.