Here are some quick and easy ways to determine if a diamond is real: 1. Use an electronic device called a diamond tester. This should be the focus point to testing is a dimaond is real or not. 2. The transparency test. This is a simple test but the diamond needs to be loose. The way to use this test is to flip the diamond upside down and keep it over the print in a newspaper. If when you look through the diamond you can read the newspaper, it is a fake diamond.