Similarly, a mounted ring can reflect more light into a diamond. This will make it hard for unskilled people to determine the clarity and color of the gemstone. Hence, it is better to choose loose diamonds, check it thoroughly, and then mount on a metal setting. There are some really simple tests with which you can tell whether or not a diamond is real.
The easiest option for this is a fog test. For this, just exhale a jet of air on to a diamond. If the diamond fogged up quickly or retained the moisture for a long time, you probably have a fake diamond. Another test that you can carry out at your home is the water test; put your diamond into a glass of water. If the gemstone sinks in, it is real. In case it floats in the water, it is either lab-created or fake.