It takes an exceptional set of circumstances to create gemstones, which is why they deserve to be valued, writes gemmologist and longtime admirer Padraic Lavin. In order for emerald to form, three rare elements that are hardly ever found together – beryllium, chromium and aluminium – must come together. But that is just the start of the story,

they will only crystallise as the incomparable green of emerald – found at its best in Columbia, and costing anything from hundreds to thousands of euro – in the unlikely event of both the correct temperature and pressure existing in that location.

Only when we realise their extraordinary rarity can we fully appreciate the true value of gems, which are so much more than what they are often mistaken for – a factory made product set in a piece of jewellery. And only then too can we fully appreciate why these rare, natural occurrences are so very appropriate in marking the most significant and special events in our lives.

Precious or Not?
Classifying gemstones as ‘precious’ or ‘semiprecious’ has no basis in either commerce or science. Garnets of low quality can be bought for a few euro and could understandably be thought of as semi –precious but then what do we say about the rare and extraordinarily beautiful green demantoid garnet that could cost many thousands? Similarly, how do we classify the poor quality half carat diamond recently bought on ebay that was grossly overpriced at €200. A top quality demantoid garnet could cost a lot more than a quality diamond of the same weight so, which is the most precious? Obviously, the terms precious and semi-precious are of no use and people in the know would never use them, as they only serve to belittle some of the most beautiful products of nature!

Traditionally, the diamond was valued for its unique properties, including hardness and brilliance, not unlike many other coloured gemstones and since diamond was not particularly rare, for a long time other coloured gems such as sapphire and ruby were more highly prized. While the big diamond finds in South Africa created an even larger supply of diamonds, which you would think would reduce the value, trade of the stone in the twentieth century became heavily regulated thanks to a single organisation: De Beers. Their market monopoly and continuous marketing campaign in the last seventy years has raised the perceived value of diamond like no other gemstone. Tanzanite is the only other gemstone to be the subject of a concerted marketing campaign, which has made a well-known gem of something that only came to the market in the early 1970s and is found only in one place on earth.

What’s in a Carat?
All gemstones, including diamonds, are sold by carat weight. There are five carats to the gram. Colour, clarity, rarity and quality of cut are the other factors that influence the price of a gemstone. Clarity with a poor colour is of little value while good colour and poor clarity is not very desirable…with one special exception – emerald, which is hardly ever found clear but is nonetheless loved for its beauty of colour. Some gems have unusual internal features that have a play of colour that changes, as you look at them. Moonstone, labradorite and opal are examples. Some gems show a bright streak of light across the stone or a sixray star that seems the float just above the stone.

The Choice is Yours
Some individuals are now choosing coloured stones as the principle stone in their engagement ring, with or without diamonds. There are few limitations on the choice of stone and most gems are seen mounted in rings. However, where considerable wear and tear is most likely, stones with a hardness of less than seven on the Mohs Scale would be best avoided. From that point of view opal, turquoise and even tanzanite, are not suitable for a ring destined to last a lifetime. The more vulnerable gems should be set in a more protective setting. A rub-over setting is often used to protect emerald, which, though quite hard, is brittle. With the exception of those mentioned, most gems that get any kind of respect will survive the day-to-day environment. The greatest risk to any gemstone is physical or thermal shock and the latter is far more likely to happen in the jeweller’s workshop than in the domestic environment.

Take Care
While the Internet is an enormous, though often bewildering, source of information, purchasing on the web, due to the big variations in quality, would be risky. If you would like to know more about purchasing gemstones I would recommend reading Renee Newman’s Gemstone Buyers Guide. The best source of gemstones is a well-established jeweller, who will a goldsmith and, most importantly, trained members of staff with a knowledge of gems and ideally a properly trained and experienced gemmologist. The gemmologist will be able to show you the characteristics and qualities of the different stones and, if necessary, deal with gemstone dealers on your behalf.

Article by:
Padraic Lavin FGA is a gemmologist jeweller, specialising in diamond and gemset jewellery and jewellery insurance valuation. He lectures in gemmology (the science of gem identification) at the National University of Ireland, Galway. Contact Mobile: 087 2393198 and E-Mail gemstone@ eircom.net.