All About Jewelry And Diamonds

How To Tell If The Diamond Is Real?

The one thought uppermost in most people’s minds as they go diamond-shopping is ‘How do I know if the diamond is real?’ While diamonds may be the most coveted of all precious stones, they are also very expensive. The huge demand for diamonds combined with their steep price has given rise to a thriving fake diamond industry.


Here are a few things you can do to tell if the diamond you wish to buy is real or fake:


Hold the diamond against the light

Diamonds have a unique way of refracting light because of their high refractive index. When a high quality real diamond is held against the light, the inner area of the stone will have a white and gray brilliance or shine while the outer area of the stone will throw off flashes of rainbow color, called fire, onto other surfaces.

If you hold the diamond against the light and you see rainbow colors inside the stone, then you know that what you have in your hand is a fake diamond. Unlike real diamonds, which have rainbow colored fires only on the outside, with fake stones, the rainbow colors are emitted from the inside.  

Cubic zirconia and moissanite are two stones that are often used as substitutes for diamonds. So how do you know if what you are buying is a real diamond or a fake diamond? It’s not all that difficult.

Cubic zirconia has a much lower refractive index than diamond so it does not have the same amount of brilliance or fire as diamond. When you hold it against the light it will not appear as bright or sparkly as diamond.

Moissanite, on the other hand, is a much higher refractive index than diamond, which causes it to appear more fiery and also more sparkly. When you place a moissanite directly under an overhead light it will emit rainbow colored sparks in all directions.

Brilliant Diamond: 3.02 ct Round Brilliant Cut Diamond Engagement Ring

Brilliant Diamond: 3.02 ct Round Brilliant Cut Diamond Engagement Ring

Breathe on the diamond

It’s interesting that a test as simple as this can tell you so much about whether you are holding a real diamond or an imitation in your hand.

Hold the stone up to your face and breathe on it through your mouth the same way you would try to fog your lenses or a glass window. If the stone stays fogged for a while, even if it is for a couple of seconds, it is more likely to be a fake diamond.  Genuine diamonds are unable to retain any heat at all so when you breathe hot air over it, the stone scatters the heat instantly and will not fog.

Try this fog test a couple of times and see what happens. If it is a real diamond, it remain clean and clear no matter how many times you breathe over it. However, an imitation diamond will keep fogging up more and more with every breath and the condensation will build up.

Use a loupe to inspect the diamond and setting

 A loupe is a special kind of magnifying glass that is generally used by jewelers and watch makers. You can get a really good look at the gem as well as the setting when you look at it through the loupe.

When looking at an unset stone through a loupe there are two things you need to look for – imperfections within the stone and the edges of the stone. If the stone is already set in jewelry, the setting and the etching are additional aspects that can reveal a lot.

Imperfections – If you see some imperfections in the gem when looking at it through the loupe, it is more likely to be a real diamond. Diamonds are formed in nature over a period of several years. When anything is formed naturally, there are bound to be imperfections and a diamond is no different. If the stone looks absolutely perfect through the loupe, chances are it is a fake diamond. This is because it can be challenging to create imperfections artificially in imitation stones.  This test can give you false results as some fake diamonds may contain imperfections during the manufacturing process. Getting the stone evaluated by an expert is advisable will confirm whether or not the stone is genuine.    

 Edges – Take a closer look at the stone’s edges through the loupe. Does the stone have sharp or rounded edges? Crisp, clean edges could indicate a real diamond. In imitation stones the edges are usually not so crisp and sharp. They tend to be more rounded.

Setting and etchings – If the diamond you are checking out is already set in jewelry, the quality of the mounting and etching can be a pretty good indication of the whether or not the stone is the real thing. Can you see any markings that indicate what metal has been used? Real diamonds are usually mounted or set in gold or platinum and the metal will have a stamp somewhere on it to specify whether it is gold or platinum. If you cannot see such etchings and the metal looks like it is gold plated or silver, it is almost certainly a fake diamond. No jeweler would set a real stone in any cheap metal.

Rub the stone on sandpaper

Diamonds are the world’s hardest material so it is hardly likely that its surface is going to get scratched by sandpaper or any other rough surface. If you rub the gem on sandpaper and the surface gets scratches, it is a sure sign that it is an imitation.

Try to read print through the stone

Place the stone with its pointed edge on a piece of newspaper. Can you see the print through the stone? If you can see the print, whether it is sharp or blurry, it is probably not an authentic diamond. There could be a few exceptions depending on the way it is cut but in general a diamond would bend the ray of light so sharply, making it impossible for you to see the black type through it. An imitation stone will allow the print to show through.

You can try this test by placing the stone over a dot made on a piece of paper. When you look directly down through a fake stone, you will be able to see a circular reflection of the dot in the gem. Through a real diamond you would not see this.

Drop the stone in water

When dropped into a container of water, a genuine diamond will sink to the bottom because of its high density. Imitation stones have a lower density and will either float at the surface or hover around somewhere in the middle of the container.

Drop the heated stone in water

Diamond is hard, tough and capable of withstanding extreme changes in temperature. Quartz, glass and other weaker materials that have lower tensile strengths are not capable of withstanding these huge temperature changes. These materials will shatter if subjected to rapid expansion and contraction.    

To test for authenticity, heat the stone over a flame for about a minute and then drop it into cold water. If the stone shatters from the inside, it is a fake diamond. If nothing happens, it may be a real diamond.

Get a heat probe test done

A heat probe test is slightly different from the above test. In this test a heat probe is used to heat the diamond for about half a minute. Because of their tight, evenly-packed crystalline structure, diamonds do not retain the heat. Instead they scatter the heat immediately and do not heat up. A replica stone on the other hand will get hot. 

While all of the above tests will give you a fairly good indication as to whether the stone you are evaluating is real or fake, none of them are 100 % conclusive. To be absolutely certain that what you are paying for is a real diamond, you must take it to a gemologist and get it professionally assessed. 

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