There are countless types of natural gemstones in the market today, besides the ubiquitous diamond. Many of these are coloured, and as such they enjoy their own popularity among people who are aficionados of a particular colour and quality. Among these are the big three—sapphires, rubies and emeralds.
Blue sapphire is formed from a compound called corundum, coloured blue by trace elements of titanium and iron. Its deep blue colour has been a popular choice for jewellery settings because of its stark contrast with brighter colours, and it continues to be well-loved today.
However, apart from blue, sapphires can also be yellow from higher concentrations of iron, or even pink in colour from trace elements of chromium. These are relatively rare and also in demand. Sapphires are found in countries like Sri Lanka, Thailand, Myanmar, Australia, Tanzania, and Madagascar.
Like pink sapphires, rubies are also made corundum, and they acquire their deep red colour from chromium. However, rubies have a much deeper intensity of colour that has made them deeply desired items from earliest history.
Depending on where rubies come from, they can exhibit a lot of variety in their colours, ranging from pinkish to purplish, as well as from dark red to almost pink. The most beautiful rubies are found in Sri Lanka and Myanmar, but they can also be found from Thailand, Vietnam, India, and many other countries in Asia and Africa.
The luscious green of an emerald has been a mainstay of jewellery collection for centuries. Formed by the mineral beryl, emeralds get their green colour from small amounts of chromium and vanadium within the crystal structure of the stone.
Symbolising rebirth and love through ancient history because green was considered the colour of life, emeralds remain the most popular green coloured gem today. Emeralds are found mainly from Colombia, Zambia, Ethiopia and Zimbabwe.
Unlike diamonds, other natural and coloured gemstones are judged on colour first and foremost. Good colour means the gemstone’s colour is pure (does not contain shades of other colours), and also that the colour is rich and intense. Good colour is also neither too light nor too dark.
Unlike diamonds where clarity is extremely important, most coloured gemstones are judged only as far as being “eye-clear”—in other words, if they appear to be clear without magnification, they are considered to be of high quality. This is because most natural gemstones invariably contain inclusions and impurities, and to find completely unblemished natural stones is incredibly rare.
Coloured gemstones are not cut for maximum brilliance, unlike diamonds. A good cut for such stones would be one that reveals the most even colour, hides inclusions, and retains most of the original stone’s weight.
Needless to say, the size of the gemstone is the single most obvious and visible sign of quality, and a stone’s value comes in part from its size as measured in carats.