Six ways to tell if your pre-loved jewellery is the real deal.

They say diamonds are a girl’s best friend. While that might be true, they don’t seem to get along with my wallet. At all.

For those of us wanting to bling up our lives without the price tag (or fiancé), there is hope: second-hand jewellery stores. These troves of hidden treasures will be your new best-kept secret whenever someone asks you where you got that gorgeous, one-of-a-kind antique ring – and we’ll do our bit to keep our lips sealed, too.

We spoke to Michael Pearce, a jewellery specialist with more than 12 years’ experience in the industry, about his top tips for anyone interested buying or selling second-hand jewellery.

Here are six things to keep in mind when evaluating jewellery, so you can figure out whether the pre-loved piece you’ve fallen in love with is actually the real deal.

1. Look for the hallmark.

When buying or selling jewellery, the first thing appraisers will look for is the hallmark and stamp. “All jewellery should have an identifying mark stating the quality of gold in the piece which tells us that it is actual carat gold and not costume or fake. Diamonds can also have identifying serial numbers to signify what it is and its authenticity. These generally come from an independent authority, like the Gemmological Institute of America (GIA) who are an international authority on diamond grading,” comments Pearce.

Apart from the hallmark, many pieces of jewellery will also come with a marker’s mark, which is the stamp signifying the artisan or company that produced the jewellery. These are more common – and also more valuable – when looking to buy or sell designer or brand-name pieces, such as Tiffany & Co or Rolex. When buying luxury, second-hand pieces such as these, they will also often come with a certificate of authenticity.

2. Test the stone.

Whether they be rings, bracelets, necklaces or earrings, often the value of pre-loved jewellery comes from the quality of the gemstones that you find in them, and the best way to test if gemstones are real is by using diamond testers. You can purchase these online for about $10.

"Makes sure to ask for a certificate of authenticity". Image: iStock.

“A diamond tester is a small, hand-held device that sends a signal through the stone to see how much heat it conducts,” explains Pearce. “Different stones conduct heat in different ways, so you can tell straight away if it’s the real deal or not. This is the most accurate way to test the difference between real diamonds and cubic zirconia, for example, because cubic zirconia don’t conduct heat at all.”

3. Look for the inclusions.

The amount of inclusions in gemstones is another way to differentiate between real and fake pieces. Inclusions are essentially the “birthmarks” of stones – any natural flaws or unique markings within the rock itself. “Natural stones, such as emeralds and sapphires, will have a number of inclusions in them, whereas synthetic stones will often be perfectly clear,” comments Pearce.

In order to figure out the amount of inclusions in a stone, you would need a high-grade magnifying glass. Jewellers and evaluators will typically use 10x loupe, which is a glass with 10-times magnification. For those of us who aren’t professionals, usually the valuation certificate will include information about a stone’s natural inclusions.

4. Measure the colour.

All gemstones have a colour grade, ranging from ‘D’ (colourless) to ‘Z’ (highly coloured), and this is one of the determinants of their value.

“When looking at diamonds in particular, it’s easy to tell whether they’re the real deal by looking at their colour,” says Pearce. “Cubic zirconia are colourless, so would register as a D on the colour chart. Almost all natural diamonds – except for the really rare and very expensive ones – will naturally be coloured to varying degrees, so whenever a diamond comes into the store, I’ll always look at it next to a cubic zirconia to see if it is coloured by comparison.”

"All gemstones have a colour grade, ranging from ‘D’ (colourless) to ‘Z’". Image: iStock.

However, the value of a coloured gemstone can vary depending on its intensity, and also what buyers are looking for. “One of the most interesting second-hand pieces I’ve ever seen was a 1.51 carat purple-pink diamond,” comments Pearce. “It was classified as a fancy-intense GIA certified diamond, and the richness of the colour was spectacular – like nothing I’ve ever seen before. Coloured diamonds are really rare, so this second-hand piece was valued at around $250k.”

5. Assess the cut.

While the cut of gemstones varies according to personal taste, the way a stone has been cut can also give an indication of the age of jewellery. “Looking at the quality and commonality of the cut of a gemstone can tell us whether we’re working with an antique piece or a modern piece,” explains Pearce. “Modern pieces are usually laser cut to precise measurements and standards, whereas antique pieces can have oddly-shaped facets and be cut in more interesting ways. This can tell us whether it’s an artisan piece, and how old the stone actually is.”

“The general rule of thumb is the older and more complicated the cut, the more valuable the stone.”

6. Get it professionally valued.

Let’s face it: most of us aren’t jewellery experts, and while keeping these rules in mind to tell whether the piece you’re selling or buying is the real deal, it can be hard for the average person to assess the market price a certain piece will fetch.

Most of us also don’t have the equipment to look for natural inclusions or hallmarks, so in order to get more bang for your buck, it always pays to get the piece professionally examined and evaluated.

“Quality second-hand jewellery merchants will always seek a third-party professional opinion on items worth over $1000. This is both to ensure peace of mind for our customers, as well as ensuring we’ve done the best possible job for them,” says Pearce.

Never underestimate the value of your possessions again. Image: iStock.

Second-hand jewellery stores can be an Aladdin’s cave for treasure-hunters; both if you’re looking for a unique, interesting piece to call your own, or if you’re interested to see just how much you can make from your pre-loved fine jewellery.

“The interesting thing is people have some really beautiful, valuable stuff lying around in boxes or in storage that they never use,” says Pearce. “You’d be surprised how valuable old jewellery is, and the kind of treasures you can find in second-hand stores.”

What are some great pre-loved items you've recently purchased?