How to identify a real diamond you pay for...
1) sets the diamond on a magazine or a piece of paper with writing on it, if you can see any lettering, the diamond is not real. Because it refracts light so easily, it should be very difficult to see anything through it.
2) Examine the diamond for imperfections. Like any other stones, diamonds have flaws in them. These small flaws only affect the clarity of diamond slightly. Beware of any diamonds that are perfectly clear, there is a high chance that you are looking at a fake one.
3) Hold the diamond in the palm of your hand, breathe I and exhale on the diamond. If the diamond is real, the fog that covers it will evaporate (gone) quickly, if the diamond is not real, it needs an extended period of time to evaporate.
4) Purchase an instrument that tests various aspects of a diamond but with a great assistance when determine whether the diamond is real.
5) Assess the sparkle of your diamond. Synthetic diamonds more sparkle than the real one.
6) Real diamonds cannot be damaged because the stone is hard. If the stone is able to damages, which mean it is not real.
7) apply the point of the diamond to a piece of glass and attempt to scratch the glass. If the glass scratches, the diamond is fake. If the glass cuts, the diamond is authentic (real).
8) A real diamond’s reflection usually shows in various shades of grey. If you see rainbow reflections, you are either dealing with a low-quality diamond or a fake one.
9) Diamond has a strong adsorption for oil and dirt. You could feel adhesive (sticky) if you touch it.
10) Drop a drop of water on the diamond; if the ball shaped water keeps for a long time, it indicates that the diamond is true, if the drop of water stays on the diamond for a few seconds, that mean it is fake one.