Emeralds are associated with new life, revitalisation, rebirth and peace. These elusive green crystals have been believed to possess talismanic properties, as if they were the gifts from the gods. Emeralds have fascinated man for more than 4,000 years. In Egypt, they were discovered in the Eastern Desert, an area later referred to as Cleopatra’s mines. Meanwhile, in South America, the Incas filled their temples with their lush green gems, believing that their gods loved smáragdos (emerald) above all else. In the 1550s, the Spanish conquistadors arrived in South America and robbed the country of its gold and emerald treasures, despite the Inca priests’ efforts to prevent the pilfering hands of the Spanish. Eventually, the highly prized emeralds made their way to India, where the Mughal rulers, and later the Maharajahs, associated the colour green with paradise and revered the emerald. Many large crystals were carved with words from the Qur’an and worn close to the skin for extra protection.

Every emerald in the world is unique, for nature never replicates. The massive forces of tectonic plate movement formed the Andes mountain range 45 million years ago and, with that pressure and combination of minerals, emerald crystals were created. Brazil and Colombia have long been known for their emeralds, amongst other gemstones, but emeralds from Zambia, which have only been mined since the 1950s, are in fact much older, having formed more than 500 million years ago.

While the origin of a gem is of gemmological interest, it is the beauty of the individual stone that matters. When buying any gemstone, colour is very subjective – it does not really matter which stone you choose, if you have a good reason for choosing it. First impressions are really important: if a stone makes you think, “Wow, that is amazing,” then that is a good first sign. But before you buy a stone, you must look at it in different light sources and from different angles; an emerald must look lively and vibrant in daylight as well as in artificial light. Emeralds can show a blue-green or a yellow-green hue; you want this colour to be even throughout the stone – not too dark and not too pale. Unlike diamonds that are judged on their lack of inclusions, emeralds are known for their inclusions.

 Elizabeth Taylor’s emerald parure, by Bulgari (1962), from Emerald: Twenty-One Centuries of Jewelled Opulence and Power (2013), by Jonathan Self, Joanna Hardy, Franca Sozzani and Hettie Judah

If I see a green stone without natural inclusions, I wonder if it is a synthetic emerald, for emeralds have what is known as jardins (gardens), as the inclusions look like branches and flowers; they are the emerald’s fingerprint. Emeralds with fewer inclusions are considered better quality gems and command a higher price, but inclusions should not be the deciding factor when buying an emerald. Though inclusions that reach the surface should be avoided as they compromise the stone’s durability, inclusions are very much part of the emerald and their formation is totally unique to that stone.

When buying a significant emerald jewel, the design should showcase the emerald. If an emerald is set in a mount that encases the whole of the stone, I would be very wary, for hiding the edge or the back of the stone may be an attempt to cover up the stone’s authenticity. It is always a good idea to find out whether the stone has its own gemmological laboratory report, which will confirm that the gem is not synthetic and whether it has been subjected to any treatments. Emeralds have been oiled for centuries to help improve their colour by diminishing the appearance of surface-reaching fissures; oiling is an accepted practice, but modern enhancements and treatments need to be disclosed as these can greatly affect a stone’s value.

Emeralds are rare and have long been a favourite of kings and queens, Maharajahs and Hollywood stars. I am often asked to name my best emerald jewel, which of course is very difficult to narrow down, but the emeralds owned by Elizabeth Taylor, I have to say, are quite exceptional. Taylor knew her gems like no one else – she just managed to get other people to buy them for her!