How do you see if is a real diamond?

There are a number of different ways to see if a diamond is real. The quickest and easier is the fog test: a real diamond will disperse the heat from your breath immediately, the setting: such as 10k, 14k or 18k stamps inside the setting, anything with a C.Z (cubic zirconia) usually indicates that the diamond is not real, a jewelers loupe and also if it has rainbow reflections if you look at it from the top. You can also take it to a jeweler and get it evaluated.