Telling the difference between a fake and real diamond is not only for the trained eye. Before making a large diamond purchase, follow certain precautions to ensure you are getting the real deal. Real diamonds have certain attributes that fake diamonds will never be able to re-create. If all else fails, having a stone appraised will ensure you are getting a genuine diamond.
Fake diamonds are man-made. They are typically synthetics, glass and cubic zirconia and can come in a variety of colours. Cultured diamonds are grown from a seed under high pressure and temperature. The natural inclusions of a real diamond must be added to cultured diamonds to simulate a genuine diamond. Cubic zirconia consists primarily of zirconium dioxide and is heaver and less hard than a real diamond.
Genuine diamonds produced in mines are rated a 10 on the Mohs Scale of Hardness. Real diamonds are graded on cut, clarity, colour and carat weight. Real diamonds will almost always show internal inclusions and blemishes, especially under 10x magnification. Real diamonds come with a certificate of authenticity from a reliable grading organisation or appraiser that can give proof and specifications of the cut, clarity, colour and carat weight.
The Light Reflection
Real diamonds sparkle much more than glass or quartz; these imitations do not bend light the way a real diamond does. If the stone is loose or not in a setting, you can place it on a newspaper upside down to see if the print is visible. If the stone is a real diamond, you will not be able to see the print on the newspaper. Also, an authentic diamond has a grey reflection and scintillation. A fake or synthetic diamond will have a rainbow reflection.
Cubic zirconia weighs roughly 1.5 times more than a genuine diamond. It is also less hard than a real diamond, so scratches on the surface of the stone are a giveaway that it is not a real diamond. Using a carat or a gem scale to compare stones of similar size will indicate which one is fake or real.
To check if a mounted stone is real or fake, look directly through the top of it. If the diamond is real, you should not be able to see the bottom of the stone. If you can see straight through the stone to the bottom, it is a synthetic or fake diamond. The mounting of a fake stone will typically be in a cheap metal. Look for a stamp inside the metal indicating whether it is gold or platinum.
If you put a diamond in water, it will sink. If you put fake diamonds in water, they will float.
If you breathe on the tone and it stays foggy for two to four seconds, the stone is a fake. Genuine diamonds quickly clear of any fog if breathed on.