The guide to buying fine jewellery

The guide to buying fine jewellery


The archaeological record shows that people have been wearing items of jewellery for at least a hundred thousand years. The one constant throughout the ages has been the bewildering array of jewellery that is available, including different metal types, styles and gems to choose from. In more recent times the choices a buyer makes have expanded even further in the digital age of ecommerce and social media channels. Despite all of this choice, people still make fundamental mistakes when buying jewellery and often pay well over the odds. This guide will demonstrate how, with a little homework, you can avoid the common pitfalls and find true value for money. The points below are intended as food for thought as you embark upon that special purchase.


(The two may appear very similar but a trained expert can tell the difference under lab conditions)

Provenance of a gemstone

When buying gemstone jewellery the origin of the stone or stones set in it are a crucial factor in determining its value. Natural gemstones are mined from the earth and are not created in a lab. Some natural gemstones can be enhanced, meaning they have been treated in some way (often with heat) to deepen or intensify their colour or improve their clarity. Enhancements and treatments are normally stated on a stone's certificate so read this carefully and ask if you are not sure of any abbreviations or acronyms. Lab grown, or synthetic, stones are those that are manmade in a laboratory. They have the same chemical, physical and optical qualities as natural gems but they are typically around 30-50% cheaper than their natural counterparts, due to the fact they are not as rare. A professional gemmologist, with laboratory equipment, can tell the difference between a natural and a synthetic stone and record this on the gem's certificate. There is nothing wrong with buying synthetic or enhanced stones, as long as the seller has disclosed this fact to the buyer (failure to do so can be fraudulent). Imitation stones are very different, they are essentially fake gemstones! The only similarity they have with natural and synthetic varieties are in their appearance. This is often achieved with lead, glass, resins and other materials that resemble the true stones and they should be avoided at all costs.


(Source: GIA education)

Treatments & Enhancements

Gemstone treatments and enhancements vary enormously but some have a very profound effect on the value of the stone. It is very common for gems to be enhanced in some way, over 90% of corundum (rubies and sapphires) have undergone some form of heat treatment. Over 90% of emeralds have been treated, or oiled, in some way. With emeralds the key is to ensure the stone has either received no treatment at all (these fetch extremely high prices) or light cedar oiling. It is advisable to avoid stones that have been filled with resins or polymers, as over time these tend to crack and distort the appearance and colour of the emerald. A light re-oiling with cedar oil every 5-10 years can actually help to protect an emerald and keep it in the best possible condition. Gemstones can be measured by carat weight or size (usually in millimetres). One carat is equal to a fifth of a gram, which is roughly equivalent to the mass of a paper clip and each carat is further divided into 100 decimals, which are usually referred to as 'points.' A 0.25 carat diamond, for example, is said to be 25 points or a 25 'pointer.' When buying gemstones it is worth considering stones that fall just short of major round numbers of carats, as these can often be significantly lower in price but aesthetically identical. A example would be a 0.98 carat stone, which would be far cheaper to buy than an identical 1.00 carat gem with similar qualities.


4 C's

In broad terms, gemstones can be valued according to the interplay of the 4 C's (cut, colour, clarity & carat). However with coloured gems it is the colour, origin and treatment that are the principle determiners of value. A 1 carat, no oil, deep green Colombian emerald, for example, would be worth significantly more than a 5 carat, minor oil, light green Zambian emerald. Smaller stones that score more highly in terms of colour, treatment and place of origin will be worth far more. Colombia has built a reputation for the finest emeralds in the world, whilst Burma (Myanmar) produces the most sought after rubies, the highest value blue sapphires come from Kashmir and the Argyle mine in Western Australia sources the best pink diamonds. These geographical origins can increase the value of a gem many times over and it is essential to check where a stone comes from prior to purchasing it.



Certification is key to making the right gemstone purchase. Many coloured gems are bought and sold around the world each day without certificates but for the inexperienced buyer this is a risky way of doing business! The GIA (Gemmological Institute of America) are one of the leading certification authorities for diamonds. Gübelin gem lab, Lucerne, Switzerland, is often regarded as the premier certifier for coloured gemstones. GCS labs in London are also very highly regarded, as are CDTec in Colombia (who specialise in the certification of emeralds).



Other considerations

It is important to factor in the tastes of the intended recipient of the jewellery, does he or she prefer contemporary designs or classical ones? Do they live a sporty or outdoor lifestyle that may lead to practicality issues when considering the design or gem selection? Diamonds have come to dominate the gem market (with a 90% share) but emeralds, rubies and sapphires are starting to mount a comeback and are actually growing in value faster than diamonds. Finally you need to think about the design and metal type for the setting, considering rose gold, yellow gold, white gold and platinum. Here your imagination can run wild!


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