The diamond industry runs on trust. Trust that these small beautiful stones hold their value, trust that their beauty is as reliable a signal of their worth as it seems to be, and trust that the smiling friendly person selling you the small stone is being truthful and honest with you. Many people are easy targets for the unscrupulous because they believe themselves to be good judges of both character and quality, not realizing quite how far or how quick a conman can be!
Judging by eye is not good enough in the diamond world, where the bare minimum is examining stones, out of their setting, and under magnification of at least ten – much more when the stone is highly rated. Many stones can sparkle with a magnificence that is indistinguishable from diamond, others have similar weights, equal densities, and so on. A layman would struggle to distinguish a good costume piece from an authentic diamond. So, how can you tell if a diamond is real anyway? A good place to start is to consult professional and impartial sites, such as the Pricescope diamond forum, where you will learn more about what is a good indicator and what is not! Let us have a look at some examples:
Diamonds do have a wonderful sparkle, and a perfectly cut diamond makes ‘hearts and arrows’ in the refractions, and they also seem to have an almost otherworldly inner fire. Trouble is, so do many other stones! And a poorly cut diamond will not sparkle as beautifully and cleanly as a well-cut synthetic moissanite stone, or carefully crafted cubic zirconia – both of which sparkle in a way very similar to diamonds!
Diamonds are known for being dense and strong, able to scratch other stones, glass, and crystal. But again, cubic zirconia and moissanite (the two most common artificial diamonds) will scratch or cut into softer materials – and being fairly dense it can be difficult to tell this way. Overly rigorous testing can actually damage a real diamond which, while strong, is still susceptible to damage.
Now we are getting closer. Diamonds, being pure carbon are heat and electricity conductive, which means that one excellent way to test fake stones is by applying a small amount of heat or a modest electrical current to the stone and seeing if the heat dissipates immediately or the current continues to flow. In both cases, the signs are good that the stone is not cubic zirconia – but moissanite is heat conductive, so to rule that out, you will have to use the electrical conductivity test. There are a number of tests to be found online, but many of them – such as exposing your diamond to an open flame and then plunging it into cold water – can actually damage your diamond, even as they prove its (now lost) value! Thermal and electrical conductivity tests should be subtle – there are small measuring devices that will take minute readings and give accurate answers, without any drama or risk of damage to your stone.
Diamond grading is so subtle, with such immense differences in value between a D-rated diamond, for example, and a H-rated one that it can be difficult to realize that to the human eye – even a trained eye – the two stones can look identical! The best solution for someone not versed in diamond grading is to ensure that they only buy authenticated and certified stones. In the USA, there are two equally well-regarded diamond certifications: one from the Gemological Institute of America, or GIA, and the other from the American Gem Society, or AGS. Any reputable jeweler will be able to provide you with a certificate that matches your diamond so you can be assured that you are buying a high-quality stone. The certificates are registered online, so you can verify the details, and each stone has a great number of points of reference that you can check to verify your purchase.