HOW TO TELL, REAL OR FAKE DIAMOND
There are a variety of different ways to tell if your diamond is real or fake. At-home tests are an excellent way of gaining information…
The truth is that no at-home tests are conclusive tests. The best way to know if a diamond is real or fake to send it to a top-tier laboratory such as GIA, AGS, IGI, HRD, EGL, etc.
You can also take a diamond to a local trusted jeweller that should be able to use a tester. Something to keep in mind that the diamond should be loose – meaning it’s removed from any setting, like a ring or stud-holder.
Are Lab Grown Diamonds Fake?
No. Lab grown diamonds are real diamonds. They are not simulants like CZ or moissanite, which you can test for with the methods below. Lab grown diamonds will pass every test as real diamonds but their value is much lower and they not considered as natural diamonds.
Home Tests
Is my diamond fake or real? Many people want quick and easy ways to answer this question. Some methods pass. Others fail. Below are some of the tests suggested, and what we think about them.
Real or Fake Diamonds?
The Water Test
The basis behind this test is that a real diamond is incredibly dense, so this test will allow you to assess the density of your gemstone from your home. Fill a tumbler up ¾ full with water and a drop the loose stone in. If it floats, it is a fake – if it sinks then you are back to step one.
The Heat Test
This test sounds scary but, if the diamond is real, you have nothing to fear.* To begin, fill a glass with cold water and put on a pair of fireproof gloves. Heat the stone for around 30-40 seconds then immediately submerge it in the cold water. A real diamond will show no reaction; a fake is likely to shatter. This rapid expansion and contraction of heat will cause weak materials like cubic zirconia to crack and shatter. A diamond is resistant to heat tests as the heat quickly disperses, leaving it unaffected by the drastic changes in temperature. Be sure to carry out this test as safely as possible.
The Fog Test
This is a less extreme test of the stone’s abilities to conduct heat. To carry out the fog test, hold the diamond between two fingers, so that it can be clearly seen, and breathe on it. If the fog immediately dissipates, it is likely that the stone is a real diamond. If the fog remains for several seconds, it means that the stone is not effectively conducting heat and is a fake.
The UV Light Test
If you have been researching certification and diamond quality, you may have heard the term fluorescence. This describes the phenomena of a diamond emitting a blue glow when viewed under UV light. This glow can range from faint to very strong. However, not all diamonds possess this quality, so an absence of this blue glow does not necessarily indicate that the diamond is a fake. It’s a fun test, but not the most conclusive.
The Read Through Test
The newspaper test, or read through test, is one of the ways you can test refractivity (a diamond’s ability to bounce, bend and refract light). Place the stone upside down onto a news paper over the lettering in a well lighted area. Be sure that there are no shadows being cast over the stone or the newspaper. If you are able to read the letters (even if there is a slight blur) the stone is fake. A real diamond will refract the light in multiple directions from its various facets. This refraction will prevent you from being able to see clearly through the diamond to read the lettering.
The Dot test
The dot test also examines the refractive properties of a stone. Draw a small dot on a piece of white paper with a pen. Lay the stone flat side down over the dot and ensure the area is well lit with no shadowing. Through the pointed end of the diamond, look down to the paper. If you can see the dot reflected inside the gemstone and it is circular, the diamond is fake. If you cannot see the dot, nor a circular reflection, it is likely that the diamond is real. Like the newspaper test, the powerful refractive properties of a natural diamond will allow the light to bounce in different directions, and this is why you will not see the dot through the diamond.
The Sparkle Test
The sparkle test is a ‘by eye’ form of testing your diamond. This is pitched as a great way to gain a better understanding of the optical properties of a diamond, as well as helping to indicate whether or not the diamond is a genuine, natural diamond. (A lab-grown diamond will be the same as a mined diamond).
Hold the diamond beneath a light source, such as a lamp, and examine how the light reflects off of the diamond. Is there a white, blinking quality to the diamond (scintillation)? Are there also reflections of rainbow light? We covet diamonds for these properties, and taking the time to examine this will give you a lot of information about the stone.
This test is best performed with a point of comparison; for example, if you have a cubic zirconia that you are able to compare with the diamond, you will be able to identify the striking differences between them. This test is not fool proof. A badly cut diamond that is heavily included and has a low color grading will not give the distinctive sparkle that expect from a diamond, and so the untrained eye may find it harder to identify these optical properties. Similarly, the quality of synthetic diamonds has improved greatly over the years, meaning that a diamond novice may be deceived (we will look closer at synthetic diamonds shortly).
What About The Scratch Test?
Perhaps one of the best-known myth tests to see if a diamond is genuine is to scratch it against a mirror or piece of glass. This method tests the hardness of one material against another and is based on the Mohs scale (the scale upon which minerals are graded in terms of hardness). Unfortunately, this test is not accurate. Glass measures at 5.5 on the Mohs scale. That means that anything with a higher score can scratch it: materials such as quartz, moissanite and cubic zirconia all rank higher than glass, meaning that they too would leave a scratch.
It is also known or been said that you can use a known diamond to destroy any fake except a synthetic diamond. But if you do that you also take the risk of scratching a real diamond with a real diamond.
EXPERT TESTS
If at-home tests are just a guideline, what can you do to get a definitive answer about whether or not your diamond is real? The best way is to ask an expert.
Local jewellers may have in-house gem specialists, but tread cautiously. Often, jewelry store staff will sometimes have limited specialist knowledge when it comes to diamonds, and very few are professional gemmologists. Do your research, and visit someone with the correct qualifications who can give you answers to all your diamond questions.
Using A Diamond Tester
A diamond tester (also known as a thermal conductivity probe) is used to measure the thermal conductivity of the gemstone. Diamonds are highly effective heat conductors and will disperse heat rapidly after being warmed (as seen in the heat test). If the gemstone disperses heat at a slower rate, it is not a genuine diamond. However, it is important to be aware that moissanite stones (diamond simulants) have a very similar ability to disperse heat, meaning that this test may not be conclusive for a moissanite/diamond test.
To use the probes, the thin metal rod is pressed against the surface of the gemstone. Usually a light gauge on the side will give you your reading. Diamond testers are quite straight forward to use and can be purchased online.
An electric conductivity test can also be performed if your local diamond expert carries the correct tool. This form of testing is more effective than a thermal test, as it can also rule out moissanite, which does not conduct electricity with the same efficacy as a diamond.
Make sure that the person using the tester know how they work as the testers are known to give false positives. The diamond must be set or in contact with some metal.
Remember that shopping through lesser known channels is high risk, and will ultimately lead to a big financial loss and huge disappointment. If a deal on a diamond seems too good to be true, it is. More importantly, a reputable lab will identify if a diamond is natural and not treated or synthetic factory grown.