If you got your diamond ring as a family heirloom or as a gift, it is not necessary for your diamond to have a certificate. If you are wondering about how can you tell if a ring has real diamonds in this case, the best option is to appraise or grade your diamond ring. Nevertheless, this will be an expensive process. Thankfully, there are some easy tests, which you can conduct right at your home. The simplest test to check whether you own a real diamond ring is the fog test. For his, keep your diamond ring close to your mouth and breathe out a puff of air on it. Now, the fog will form on the surface of your diamond because of the moisture and heat in your breath. If this vapor dissipates right away, the diamond in your ring is real. This is because of the ability of diamonds to conduct heat effectively. In the case the fog remains on the stone for a couple of seconds, you probably have a fake diamond. In order to confirm this, it is recommended to consult a gemologist right away.