You no doubt recall those scenes in movies when a person tests the authenticity of a pearl necklace by running it through their teeth. If the pearls are smooth then they are not genuine since real pearls must catch on the teeth, as will soon be explained. But this isn’t necessarily the case in the real world. So away from the silver screen, how can you spot genuine pearls?
- genuine pearls reach a maximum size of approx. 1.5 cm
- the shape and surface of a genuine pearl is not perfect
- fake pearls are generally perfectly round and smooth
- the coloured surface often peels off on imitation pearls (especially around the hole)
- genuine pearls have a high lustre and a vivid appearance and under a lamp they distinctly reflect light
- genuine pearls are as a rule heavier than their imitations
- genuine pearls are cold when you put them on
- necklaces, stands and bracelets made from genuine pearls are knotted and tightened
How are genuine pearls created
Pearls are natural gemstones made from living organisms. They form inside the shells of sea and freshwater gastropods. Today, almost all pearls used in jewellery are artificially cultured, which however doesn’t mean that they are not genuine. Artificial pearl cultivation means that something called a core is inserted into the shell. The natural process of how a pearl is created is therefore simulated, whereby a foreign body such as a grain of sand enters the shell. The process of a pearl being created is then actually the protection mechanism of molluscs. That small grain or bead will be coated in layers of nacre by the oyster until it reaches its final form, which may not always be round.
Farms that specialise in pearl production use two methods of cultivation. With the ‘seed method’, a fragment of another mollusc is inserted into the shell. After about a year, the pearl which has formed is taken out and put into another shell where the coating with nacre continues. This can result in relatively large pearls. In the ‘bead method’, a bead is cut from another shell and then inserted into the mollusc. The pearl forms faster in this manner, since the desired layer of nacre is no thicker than 1 mm. Despite this however, such pearls are genuine and considered to be of quality.
The fact that pearls are formed inside the shell of a mollusc tells us that the size of pearls has its limits. Genuine pearls are no more than 1 cm plus a couple of millimetres in diameter. If a pearl has a diameter of 2 cm, it is probably not genuine.
Nature is not perfect
Pearls of various shapes and colours form via the methods described above. And it is the shape of the pearl that is another distinguishing feature which can reveal to us a pearl’s natural origins. The real ones are not perfect. They are not perfectly round and they do not have a perfectly smooth surface. They often have various ‘grooved rings’ all the way around them, numerous small dimples, they differ in size, and if you look at them under a magnifying glass, you will often see the structure of the nacre. The degree of these imperfections determines the quality of the pearl and also helps us distinguish different types of pearls.
When you say the word pearl, most people imagine something small and white with a perfectly round shape. Sea pearls, which are called Akoya, are closest to this idea. The freshwater ones, by contrast, are not as round and often have bigger surface imperfections. The pearls of the South Pacific are characterised by their golden colour while Tahitian pearls can be recognised by their dark colour and metallic shine.
And we can recognise the authenticity of pearls by their lustre. Due to a pearl’s layering structure, all genuine pearls give off a lively impression, reflect the light and shine. If a pearl is not genuine, it does not have these properties and gives off a dull, artificial impression. It reflects light only on the surface and thereby resembles glass. Try to look at a pearl under a lamp. You should take note of how much light is reflected on its surface.
Assessing a pearl’s quality
And how do you find out if a pearl is good quality? Merchants sort pearls into groups according to their quality and label each group with a code. The highest quality pearls are designated as AAA, then after these come AA, and finally A. To be even more exact, a + sign is also often used. AA+ pearls are better than AA, but of lesser quality than AAA pearls. With Tahitian pearls we also find classifications of A – D, where A stands for excellent quality and D the lowest.
The price of pearls depends on their size, shape (symmetry), colour and lustre. In general, the thicker the nacre layer, the greater the lustre of the pearl. Pearls which have only a very thin layer of nacre may also appear on the market. We recognise these pearls by a so-called blinking which occurs when we roll the pearl between our fingers. In pearls where corners have been cut during their formation, the colour of the core shines through, so a dark spot appears on the pearl at a certain angle. These pearls might therefore be genuine but they are of very low quality.
Other distinguishing features between genuine and fake pearls
Unfortunately, in addition to poor quality pearls, fake pearls also exist. We can usually distinguish them from real pearls because they have a synthetic surface and are perfectly round. What’s more, the colour surface around the hole often peels off. However these days, it is possible to encounter better quality fakes. Fake pearls can also be lighter than genuine ones. A genuine pearl necklace really has some weight to it. Another good distinguishing sign is also the fact that genuine pearls are cold. When you put on a necklace, the pearls will feel cold at first before your skin warms them up.
There are also a few destructive methods to test whether a pearl is genuine or not. You could cut the pearl in half and examine the nacre layers under a magnifying glass. If no layers appear, the pearl is not genuine. Another test is based on the composition of the pearl - it is chemically a form of calcium carbonate with protein. Pearls therefore dissolve in acids and bases. So you could throw one pearl into a glass of vinegar, as did Cleopatra during a bet with Mark Anthony. If the pearl dissolves, you have just lost a real pearl. If nothing happens to it, you can take the fake pearl out of the glass, wash it, and do with it as you see fit.
Knotting and tightening
When it comes to pearl strands, pay immediate attention to whether the pearls have been strung in a knotted style, in other words that there is a knot between each pearl. It needs to be there so that the pearls do not scratch each other and in the event that your pearl jewellery breaks, all of the pearls don’t fall out and get lost. If the strand of pearls is not knotted, then the pearls in question are cheap and may not even be genuine.
A quality strand of pearls should also be tightened. This means that if you pull on the strand slightly, no gaps between the pearls and knots appear. If the knots are not tightened, the pearl necklace or bracelet will soon become slack. It then looks very unsightly and can easily break.