There’s no doubt the emerald is a captivating gemstone. Cleopatra loved them; the Mughals associated their colour with Paradise; and the Incas believed their goddess prized them above all else. Though it’s an unconventional option for an engagement ring, an emerald can make a striking statement. Halle Berry, Jackie Kennedy and Zoe Saldana have all chosen them to great effect. But emeralds are very different to diamonds, rubies or sapphires, and clients should make sure they understand their unique properties before committing to such a bold choice.
The first thing to note is that the Gemological Institute of America defines emerald as a ‘Type 3’ gemstone. This means that it’s very rare to find an emerald that is completely free of blemishes (or ‘inclusions’) that are visible to the naked eye. These inclusions can be tiny fractures or cleavages, growth lines in the crystal, or mineral impurities. This is simply the nature of emerald, and it’s unfair to judge it by the same clarity standards that are applied to other gemstones such as diamonds.
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If the inclusions are very large or too prominent then they will disfigure the stone. But small inclusions should be seen as the emerald’s unique ‘fingerprints’, created naturally when the crystal formed beneath the earth’s crust. Emeralds that are almost totally “clean” are unusual, and very expensive, so if you hate the idea of any visible blemishes, then emerald is probably the wrong gemstone for you.
Another consideration is that the inclusions within an emerald are natural weak spots within the crystal. If an emerald gets knocked against a hard object, it’s possible for an inclusion to open up, and become more apparent. This compounds the fact that even the ‘cleanest’ emerald will never be the hardest of gemstones. With a Mohs Hardness Score of 7.5-8.0, emerald lags well behind ruby and sapphire (9), and doesn’t come close to diamond (10). While careless handling can damage any engagement ring, clients who chose emerald need to be particularly careful to avoid scratching or chipping the gemstone
If you are happy to live with some minor blemishes, and are prepared to take good care of your ring, the next thing to think about is your emerald’s colour. Emerald is composed of beryl with trace elements of chromium, vanadium, and iron, and it’s the relative quantities of these elements that determine the stone’s colour. Without them it technically isn’t an emerald at all, but a ‘green beryl’ which has a much lower market value.
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If you find a stone with good colour and clarity, the final aspect to consider is whether or not it has been enhanced through some treatment.. If an emerald has disfiguring inclusions that reach the surface, these might be filled with resin or glass to improve the stone’s appearance. Unfortunately this can make the stone vulnerable to heat, changes in air pressure, and a wide range of chemicals.
Another potential problem is the use of coloured dyes to enhance the saturation of emeralds. These dyes can often be dissolved by chemicals such as alcohol or acetone, and exposure to strong sunlight can also cause them to fade.
Many emeralds are submerged in oil at the point when they are cut, to mask inclusions and enhance colour. This process is centuries-old and needn’t necessarily be a problem, but like any form of treatment, it should certainly be disclosed to the consumer. Over time, the oil will tend to dry out, and the stone will eventually need to be re-oiled. Luckily this isn’t a difficult or expensive process.
A jeweller positioning an emerald in a ring
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Emeralds are wonderful gems, but perhaps more than any other gemstone they require a bit of specialist knowledge if you are going to get it right. Consumers should be careful, but shouldn’t be discouraged - if you’re looking for a striking and distinctive engagement ring, an emerald could be a great choice.
* This article is a guest post by David Rhode, of ethical jeweller Ingle & Rhode)
If you like this post check out my article The Secret To Buying The Perfect Wedding Ring - The Diary Of A Jewellery Lover